Coating solution for non-light-emitting organic semiconductor device, organic transistor, compound, organic semiconductor material for non-light-emitting organic semiconductor device, material for organic transistor, method for manufacturing organic transistor, and method for manufacturing organic semiconductor film

ABSTRACT

(In Formula (2), R11 and R12 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxy group and may have a substituent, and an aromatic portion in Formula (2) may be substituted with a halogen atom.)

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. patent applicationSer. No. 15/943,968 filed Apr. 3, 2018, which is Divisional Applicationof U.S. patent application Ser. No. 15/274,016 filed Sep. 23, 2016,which is a Continuation of PCT International Application No.PCT/JP2015/059298, filed on Mar. 26, 2015, which claims priority under35 U.S.C. Section 119(a) to Japanese Patent Application No. 2014-063112filed on Mar. 26, 2014 and Japanese Patent Application No. 2015-049035filed on Mar. 12, 2015. Each of the above applications is herebyexpressly incorporated by reference, in its entirety, into the presentapplication.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a coating solution for anon-light-emitting organic semiconductor device, an organic transistor,a compound, an organic semiconductor material for a non-light-emittingorganic semiconductor device, a material for an organic transistor, amethod for manufacturing an organic transistor, and a method formanufacturing an organic semiconductor film. Specifically, the presentinvention relates to a compound having athieno[3,2-f:4,5-f′]bis[1]benzothiophene skeletal structure and to acoating solution for a non-light-emitting organic semiconductor device,an organic transistor, an organic semiconductor material for anon-light-emitting organic semiconductor device, a material for anorganic transistor, a method for manufacturing an organic transistor,and a method for manufacturing an organic semiconductor film which use acompound having a thieno[3,2-f:4,5-f′]bis[1]benzothiophene skeletalstructure.

2. Description of the Related Art

Devices using organic semiconductor materials are drawing greatattention because they are expected to be superior in various aspects todevices using inorganic semiconductor materials of the related art suchas silicon. Examples of the devices using organic semiconductormaterials include a photoelectric conversion element such as an organicthin-film solar cell or a solid-state imaging element using organicsemiconductor materials as photoelectric conversion materials, anorganic transistor (referred to as an organic thin-film transistor insome cases) having non-light-emitting properties (in the presentspecification, “non-light-emitting” refers to properties by which aluminous efficiency of equal to or less than 1 lm/W is obtained in acase where electric currents are applied to a device at a currentdensity of 0.1 mW/cm² at room temperature in the atmosphere;non-light-emitting organic semiconductor devices mean organicsemiconductor devices excluding light-emitting organic semiconductordevices such as organic electroluminescence elements), and the like.Compared to the devices using inorganic semiconductor materials, thedevices using organic semiconductor materials are likely to make itpossible to prepare large area elements at lower temperature and lowercosts. Furthermore, the characteristics of the materials can be easilychanged by varying the molecular structure thereof. Therefore, thematerials show a wide variation and can realize functions or elementsthat cannot be obtained by inorganic semiconductor materials.

Regarding organic transistor materials, the use of compounds having afused ring in a semiconductor active layer is examined so as to improvecarrier mobility and to improve transistor performances.

As materials for an organic transistor, compounds having athieno[3,2-f:4,5-f′]bis[1]benzothiophene (hereinafter, referred to asTBBT as well) structure on the inside thereof are known. For example,Tetrahedron 66 (2010) 8778-8784 discloses a method for synthesizing acompound C6-TBBT or C12-TBBT obtained by substitutingthieno[3,2-f:4,5-f′]bis[1]benzothiophene with an alkyl group having 6carbon atoms or an alkyl group having 12 carbon atoms respectively, anddiscloses absorption/emission spectra and cyclic voltammetry (CV) asphysical properties of the compound. Tetrahedron 66 (2010) 8778-8784describes the application of the compound to an organic transistor inthe introduction part of the document. However, the document merelydescribes the measurement of the absorption/emission spectra or theoxidation-reduction potential of the solution, but does not describe theformation of a film, the physical properties of the film, the evaluationof organic transistor characteristics such as carrier mobility, and thelike.

SUMMARY OF THE INVENTION

Under the circumstances described above, the inventors of the presentinvention examined organic transistors using the compound described inTetrahedron 66 (2010) 8778-8784. As a result, the inventors found that,even if a coating film is formed using a solution, which is formeasuring the oxidation-reduction potential or absorption/emissionspectra by using the compound having a TBBT structure on the insidethereof, as it is, carrier mobility cannot be increased. The inventorsfound that, accordingly, carrier mobility needs to be further improved.

An object of the present invention is to provide an organic transistorhaving high carrier mobility.

As a result of conducting intensive examination for achieving the aboveobject, the inventors obtained knowledge that, by substituting askeleton having a thieno[3,2-f:4,5-f′]bis[1]benzothiophene (hereinafter,referred to as TBBT as well) structure on the inside thereof with aspecific substituent, an organic transistor having high carrier mobilitycan be obtained, and accomplished the present invention.

The present invention as specific means for achieving the above objecthas the following constitution.

[1] A coating solution for a non-light-emitting organic semiconductordevice comprising a compound represented by the following Formula (2)and a solvent having a boiling point of equal to or higher than 100° C.;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and an aromatic portion in Formula (2)may be substituted with a halogen atom.

[2] The coating solution for a non-light-emitting organic semiconductordevice described in [1], in which the compound represented by Formula(2) preferably satisfies the following condition A, B, C, or D;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom;

condition B: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 2 to 4 carbonatoms;

condition C: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent a substituted alkyl group having 1or 2 carbon atoms;

condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.

[3] The coating solution for a non-light-emitting organic semiconductordevice described in [2], in which the compound represented by Formula(2) preferably satisfies the following condition A;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[4] The coating solution for a non-light-emitting organic semiconductordevice described in [3], in which in Formula (2), R¹¹ and R¹² eachpreferably independently have 3 to 30 carbon atoms in total andrepresent an unsubstituted linear alkyl group having an even number ofcarbon atoms within a range of 8 to 10 carbon atoms or an unsubstitutedlinear alkyl group having an odd number of carbon atoms within a rangeof 3 to 15 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[5] The coating solution for a non-light-emitting organic semiconductordevice described in [3] or [4], in which in Formula (2), R¹¹ and R¹²each preferably independently have 3 to 30 carbon atoms in total andrepresent a linear alkyl group having 3 to 15 carbon atoms substitutedwith a substituent through an ether structure or an ester bond.

[6] The coating solution for a non-light-emitting organic semiconductordevice described in [2], in which the compound represented by Formula(2) preferably satisfies the following condition B;

condition B: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 2 to 4 carbonatoms.

[7] The coating solution for a non-light-emitting organic semiconductordevice described in [2], in which the compound represented by Formula(2) preferably satisfies the following condition C;

condition C: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent a substituted alkyl group having 1or 2 carbon atoms.

[8] The coating solution for a non-light-emitting organic semiconductordevice described in [7], in which in Formula (2), R¹¹ and R¹² eachpreferably independently have 3 to 30 carbon atoms in total andrepresent an alkyl group having 1 or 2 carbon atoms substituted with asubstituent through an ether structure or an ester bond.

[9] The coating solution for a non-light-emitting organic semiconductordevice described in [2], in which the compound represented by Formula(2) preferably satisfies the following condition D;

condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.

[10] The coating solution for a non-light-emitting organic semiconductordevice described in [9], in which in Formula (2), R¹¹ and R¹² eachpreferably independently have 3 to 30 carbon atoms in total, R¹¹preferably represents an unsubstituted linear alkyl group, and R¹²preferably represents a substituted or unsubstituted linear or branchedalkyl group different from R¹¹.

[11] The coating solution for a non-light-emitting organic semiconductordevice described in [10], in which in Formula (2), R¹¹ and R¹² eachpreferably independently have 3 to 30 carbon atoms in total andrepresent an unsubstituted linear alkyl group, and R¹¹ and R¹²preferably have different structures.

[12] An organic transistor comprising a compound represented by thefollowing Formula (2) in a semiconductor active layer;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[13] The organic transistor described in [12], in which the compoundrepresented by Formula (2) preferably satisfies the following conditionA;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[14] A compound which is represented by the following Formula (2) andsatisfies the following condition A, B, C, or D;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and

an aromatic portion in Formula (2) may be substituted with an halogenatom;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom;

condition B: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 2 to 4 carbonatoms;

condition C: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent a substituted alkyl group having 1or 2 carbon atoms;

condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.

[15] The compound described in [14], in which the compound representedby Formula (2) preferably satisfies the following condition A;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[16] An organic semiconductor material for a non-light-emitting organicsemiconductor device containing the compound described in [14] or [15].

[17] A material for an organic transistor containing the compounddescribed in [14] or [15].

[18] A coating solution for a non-light-emitting organic semiconductordevice containing the compound described in [14] or [15].

[19] An organic transistor containing the compound described in [14] or[15] in a semiconductor active layer.

[20] A method for manufacturing an organic transistor, comprising a stepof preparing a semiconductor active layer by coating a substrate withthe coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11] and [18] and drying thecoating solution.

[21] A method for manufacturing an organic semiconductor film, in whichin a state where a distance between a substrate A and a member B notbeing fixed to the substrate A is kept constant or in a state where thesubstrate A and the member B are caused to remain in contact with eachother, a coating solution, which contains a compound represented by thefollowing Formula (2) and a solvent having a boiling point of equal toor higher than 100° C., is dropped onto a portion within the surface ofthe substrate A such that the coating solution contacts both of thesubstrate A and the member B, and the dropped coating solution is slowlydried, such that crystals of the compound represented by Formula (2) areprecipitated and a semiconductor active layer is formed;

here, as long as the distance between the substrate A and the member Bis kept constant or as long as the substrate A and the member B arecaused to remain in contact with each other, the positional relationshipbetween the substrate A and the member B may be maintained or changedwhen the coating solution is dropped or dried;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

[22] A method for manufacturing an organic semiconductor film, in whichin a state where a distance between a substrate A and a member B notbeing fixed to the substrate A is kept constant or in a state where thesubstrate A and the member B are caused to remain in contact with eachother, a coating solution, which is prepared by dissolving the compounddescribed in [14] or [15] in a solvent, is dropped onto a portion withinthe surface of the substrate A such that the coating solution contactsboth of the substrate A and the member B, and the dropped coatingsolution is slowly dried, such that crystals of the compound describedin [14] or [15] are precipitated and a semiconductor active layer isformed;

here, as long as the distance between the substrate A and the member Bis kept constant or as long as the substrate A and the member B arecaused to remain in contact with each other, the positional relationshipbetween the substrate A and the member B may be maintained or changedwhen the coating solution is dropped or dried.

The coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11], in which the solvent havinga boiling point of equal to or higher than 100° C. is preferably anon-halogen-based solvent.

The coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11] and [18], in which theconcentration of the compound represented by Formula (2) is preferablyequal to or greater than 0.4% by mass.

The coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11] and [18] that preferablycontains two or more kinds of compound represented by Formula (2).

The coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11] and [18] that preferably hasa viscosity of equal to or higher than 10 mPa·s.

The coating solution for a non-light-emitting organic semiconductordevice described in any one of [1] to [11] and [18] that preferablycontains a polymer.

A coating film comprising a compound represented by the followingFormula (2);

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

A coating film comprising the compound described in [14] or [15].

According to the present invention, it is possible to provide an organictransistor having high carrier mobility.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a section of an exemplary structureof an organic transistor manufactured as a substrate for measuring FETcharacteristics in examples of the present invention.

FIG. 2 is a schematic view showing a section of the structure of theorganic transistor manufactured as a substrate for measuring FETcharacteristics in examples of the present invention.

FIGS. 3A to 3C are schematic views showing an example of a method formanufacturing an organic semiconductor film of the present invention.Specifically, FIGS. 3A to 3C are schematic views showing an aspect inwhich in a state where a distance between a substrate A and a member Bnot being fixed to the substrate A is kept constant, a coating solutionis dropped onto a portion within the surface of the substrate A suchthat the coating solution contacts both of the substrate A and themember B, and the dropped coating solution is slowly dried in a statewhere the positional relationship between the substrate A and the memberB is maintained.

FIGS. 4A to 4C are schematic views showing another example of the methodfor manufacturing an organic semiconductor film of the presentinvention. Specifically, FIGS. 4A to 4C are schematic views showing anaspect in which in a state where the substrate A and the member B remainin contact with each other, a coating solution is dropped onto a portionwithin the surface of the substrate A such that the coating solutioncontacts both of the substrate A and the member B, and the droppedcoating solution is slowly dried in a state where the positionalrelationship between the substrate A and the member B is maintained.

FIGS. 5A to 5C are schematic views showing another example of the methodfor manufacturing an organic semiconductor film of the presentinvention. Specifically, FIGS. 5A to 5C are schematic views showing anaspect in which in a state where the substrate A and the member B remainin contact with each other, a coating solution is dropped onto a portionwithin the surface of the substrate A such that the coating solutioncontacts both of the substrate A and the member B, and the droppedcoating solution is slowly dried by changing the positional relationshipbetween the substrate A and the member B.

FIG. 6 is a schematic view showing an example of the substrate A and themember B used in the method for manufacturing an organic semiconductorfilm of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention will be specifically described. Theconstituents described below will be explained based on representativeembodiments or specific examples, but the present invention is notlimited to the embodiments. In the present specification, a range ofnumerical values described using “to” means a range including thenumerical values listed before and after “to” as a lower limit and anupper limit respectively.

In the present invention, unless otherwise specified, a hydrogen atomused in the description of each formula represents a hydrogen atomincluding an isotope (deuterium atom or the like). Furthermore, an atomconstituting a substituent represents an atom including an isotopethereof.

[Coating Solution for Non-Light-Emitting Organic SemiconductorDevice/Organic Transistor/Compound]

A first aspect of a coating solution for a non-light-emitting organicsemiconductor device of the present invention contains a compoundrepresented by the following Formula (2) and a solvent having a boilingpoint of equal to or higher than 100° C.;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

A second aspect of the coating solution for a non-light-emitting organicsemiconductor device of the present invention is a coating solution fora non-light-emitting organic semiconductor device containing a compoundof the present invention that will be described later.

A first aspect of an organic transistor of the present inventioncontains a compound represented by the following Formula (2) in asemiconductor active layer.

In Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and an aromatic portion in Formula (2)may be substituted with a halogen atom.

In the first aspect of the organic transistor of the present invention,the semiconductor layer may contain the compound represented by Formula(2) and a solvent having a boiling point of equal to or higher than 100°C. or may contain the compound represented by Formula (2) (here, acompound satisfying a condition A, B, C, or D is excluded) and a solventhaving a boiling point of equal to or higher than 100° C.

Furthermore, in the first aspect of the organic transistor of thepresent invention, the semiconductor active layer is preferablymanufactured using a solution containing the compound represented byFormula (2) and a solvent having a boiling point of equal to or higherthan 100° C., and is more preferably manufactured using a solutioncontaining the compound represented by Formula (2) (here, a compoundsatisfying a condition A, B, C, or D is excluded) and a solvent having aboiling point of equal to or higher than 100° C.

A second aspect of the organic transistor of the present invention is anorganic transistor containing a compound of the present invention thatwill be described later in a semiconductor active layer.

By adopting the aforementioned constitution, the organic transistor ofthe present invention exhibits high carrier mobility. In addition, thecoating solution for a non-light-emitting organic semiconductor deviceof the present invention can provide the organic transistor of thepresent invention having high carrier mobility. Presumably, though thepresumption is not restricted by any theory, in the first aspect, if thecompound represented by Formula (2) having a specific substituent isused, an organic transistor having high carrier mobility is obtainedeven though the reason has not yet been clarified in detail (theimprovement of solubility or the like is considered to exert aninfluence). In the first aspect, in order to rapidly dry the solution atthe time of forming a film, it is preferable to use a solvent having ahigher boiling point. Particularly, in a case where the compoundrepresented by Formula (2) (here, a compound satisfying a condition A,B, C, or D is excluded) is used in the semiconductor active layer, anorganic transistor having high carrier mobility is more easily obtained.Furthermore, presumably, in the second aspect, if a compound of thepresent invention having a specific substituent that will be describedlater is used, an organic transistor having high carrier mobility isobtained, even though the reason has not yet been clarified in detail(the improvement of solubility or the like is considered to exert aninfluence).

It cannot be said that being useful as a material of an organicelectroluminescence (EL) element means being useful as a semiconductormaterial for an organic transistor. This is because the characteristicsrequired for an organic compound vary between an organic EL element andan organic transistor. A mobility of about 10⁻³ cm²/Vs is enough fordriving an organic EL element, and for improving organic ELcharacteristics, it is more important to improve luminous efficiencythan to improve charge transport properties. Therefore, an elementhaving high luminous efficiency and resulting in uniform in-planeluminescence is required. Generally, organic compounds having highcrystallinity (high mobility) cause luminescence defectiveness such asnon-uniform in-plane field intensity, non-uniform luminescence, andquenching of luminescence. Therefore, as materials for an organic ELelement, those having low crystallinity but having high amorphousness(low mobility) are desirable. In contrast, in a semiconductor materialfor an organic transistor, extremely high mobility is desired.Accordingly, an organic compound showing highly ordered moleculararrangement and having high crystallinity is required. Furthermore, forthe expression of high carrier mobility, a π-conjugate plane ispreferably upright against a substrate.

First, the coating solution for a non-light-emitting organicsemiconductor device of the present invention that can also be used as acoating solution in a method for manufacturing an organic semiconductorfilm of the present invention that will be described later will beexplained.

Hereinafter, the first and second aspects of the coating solution for anon-light-emitting organic semiconductor device of the present inventionwill be comprehensively described.

<Compound Represented by Formula (2)>

The compound represented by the following Formula (2) will be described.

In Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and an aromatic portion in Formula (2)may be substituted with a halogen atom.

Preferred aspects of the structure of the compound represented byFormula (2) will be described.

In Formula (2), the alkyl group represented by R¹¹ and R¹² is notparticularly limited. The alkyl group is preferably an alkyl grouphaving 1 to 30 carbon atoms and may be linear, branched, or cyclic. InFormula (2), the alkyl group represented by R¹¹ and R¹² has 3 to 30carbon atoms in total. The alkyl group is more preferably anunsubstituted linear alkyl group having an even number of carbon atomswithin a range of 8 to 10 carbon atoms, an unsubstituted linear alkylgroup having an odd number of carbon atoms within a range of 3 to 15carbon atoms, a substituted linear alkyl group having 3 to 15 carbonatoms, or a substituted or unsubstituted branched alkyl group having 3to 18 carbon atoms. A particularly preferred range of the alkyl grouprepresented by R¹¹ and R¹² is the same as the range in which a conditionA, B, C, or D, which will be described later, is satisfied.

In Formula (2), the alkenyl group represented by R¹¹ and R¹² is notparticularly limited. The alkenyl group is preferably an alkenyl grouphaving 2 to 30 carbon atoms, more preferably an alkenyl group having 3to 18 carbon atoms, and particularly preferably an alkenyl group having5 to 13 carbon atoms.

In Formula (2), the alkynyl group represented by R¹¹ and R¹² is notparticularly limited. The alkynyl group is preferably an alkynyl grouphaving 2 to 30 carbon atoms, more preferably an alkynyl group having 3to 18 carbon atoms, and particularly preferably an alkynyl group having5 to 13 carbon atoms.

In Formula (2), the alkoxy group represented by R¹¹ and R¹² is notparticularly limited. The alkoxy group is preferably an alkoxy grouphaving 1 to 30 carbon atoms, more preferably an alkoxy group having 3 to18 carbon atoms, and particularly preferably an alkoxy group having 5 to13 carbon atoms.

In the compound represented by Formula (2), each of R¹¹ and R¹² ispreferably an alkyl group.

In a case where the alkyl group, the alkenyl group, the alknyl group, orthe alkoxy group represented by R¹¹ and R¹² in Formula (2) further has asubstituent, the substituent is not particularly limited. Examples ofthe substituent include a halogen atom, an alkenyl group (including anethenyl group, a 1-pentenyl group, a 1-heptanyl group, a cycloalkenylgroup, a bicycloalkenyl group, and the like), an alkynyl group(including a 1-pentynyl group, a trimethylsilylethynyl group, atriethylsilylethynyl group, a tri-i-propylsilylethynyl group, a2-p-propylphenylethynyl group, and the like), an aryl group (includingan aryl group having 6 to 20 carbon atoms such as a phenyl group, anaphthyl group, a p-pentylphenyl group, a 3,4-dipentylphenyl group, ap-heptoxyphenyl group, a 3,4-diheptoxyphenyl group, and the like), ahetero ring group (may be referred to as a heterocyclic group as well,including a 2-hexylfuranyl group and the like), a cyano group, ahydroxyl group, a nitro group, an acyl group (including a hexanoylgroup, a benzoyl group, and the like), an alkoxy group (including abutoxy group and the like), an aryloxy group (including a phenoxy groupand the like), a silyloxy group, a heterocyclic oxy group, an acyloxygroup, a carbamoyloxy group, an amino group (including an anilinogroup), an acylamino group, an aminocarbonylamino group (including aureido group), alkoxy- and aryloxycarbonylamino groups, alkyl- and arylsulfonylamino groups, a mercapto group, alkyl- and arylthio groups(including a methylthio group, an octylthio group, and the like), aheterocyclic thio group, a sulfamoyl group, a sulfo group, alkyl- andaryl sulfinyl groups, alkyl- and aryl sulfonyl groups, alkyloxy- andaryloxycarbonyl groups, a carbamoyl group, aryl- and heterocyclic azogroup, an imido group, a phosphino group, a phosphinyl group, aphosphinyloxy group, a phosphinylamino group, a phosphono group, a silylgroup (a ditrimethylsiloxy methylbutoxy group), a hydrazino group, aureido group, a boronic acid group (—B(OH)₂), a phosphate group(—OPO(OH)₂), a sulfate group (—OSO₃H), and other known substituents.Among these, a halogen atom, an alkoxy group, an acyloxy group, and analkyloxycarbonyl group are particularly preferable, and a halogen atomand an alkoxy group are most preferable.

These substituents may further have the substituents described above.

In the compound represented by Formula (2), an aromatic portion inFormula (2) may be substituted with a halogen atom, and as the halogenatom, a fluorine atom is preferable. The number of carbon atomssubstituting the aromatic portion in Formula (2) is preferably 0 to 6,more preferably 0 to 4, particularly preferably 0 to 2, and moreparticularly preferably 0.

Even in a case where the aromatic portion in Formula (2) is substitutedwith a substituent other than a halogen atom, an organic transistorhaving high carrier mobility is obtained as in a case where the aromaticportion in Formula (2) is unsubstituted or substituted with a halogenatom, and functions such as high solubility can be imparted to thecompound represented by Formula (2).

In the compound represented by Formula (2), even in a case where athiophene ring portion in which R¹¹ or R¹² in Formula (2) is substitutedis further substituted with a substituent other than R¹¹ and R¹², anorganic transistor having high carrier mobility is obtained as in a casewhere the thiophene ring portion in which R¹¹ or R¹² is substituted isunsubstituted, and functions such as high solubility can be imparted tothe compound represented by Formula (2).

(Compound of the Present Invention)

In the present invention, the compound represented by Formula (2)preferably satisfies the following condition A, B, C, or D;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom;

condition B: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 2 to 4 carbonatoms;

condition C: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent a substituted alkyl group having 1or 2 carbon atoms;

condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.

The compound satisfying the condition A, B, C, or D is a novel compoundand referred to as a compound of the present invention. That is, thecompound of the present invention is a compound which is represented byFormula (2) and satisfies the following conditions A, B, C, or D. In theorganic transistor of the present invention, the compound of the presentinvention is contained in a semiconductor active layer which will bedescribed later. That is, the compound of the present invention can beused as a material for an organic transistor.

Particularly, unlike the compound C6-TBBT or C12-TBBT, described inTetrahedron 66 (2010) 8778-8784, obtained by substitutingthieno[3,2-f:4,5-f′]bis[1]benzothiophene with an alkyl group having 6carbon atoms or an alkyl group having 12 carbon atoms respectively, thecompound of the present invention further improves carrier mobility inthe organic transistor of the present invention by being contained inthe semiconductor active layer.

According to the inventors of the present invention, the reason isassumed to be as below, although the present invention is not restrictedby any reason. By selecting a specific alkyl chain length or shape thatthe compound of the present invention may satisfy, an orbital overlapgreatly occurs between molecules, and as a result, carrier mobility canbe further improved in the organic transistor of the present invention.

Hereinafter, the conditions A, B, C, and D as preferred aspects of thecompound represented by Formula (2) will be described.

(Condition A)

In the present invention, the compound represented by Formula (2) morepreferably satisfies the following condition A;

condition A: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 8 to 10 carbonatoms, an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 3 to 15 carbon atoms, a substitutedlinear alkyl group having 3 to 15 carbon atoms, or a substituted orunsubstituted branched alkyl group having 3 to 18 carbon atoms, and

an aromatic portion in Formula (2) may be substituted with a halogenatom.

The unsubstituted linear alkyl group having an even number of carbonatoms within a range of 8 to 10 carbon atoms that is represented by R¹¹and R¹² is preferably a linear alkyl group having 8 or 10 carbon atoms,and particularly a linear alkyl group having 10 carbon atoms. Theunsubstituted linear alkyl group is preferably a long-chain alkyl groupthat falls into the above range, and particularly preferably along-chain linear alkyl group, because then the molecular linearity isimproved, and hence carrier mobility can be improved.

The unsubstituted linear alkyl group having an odd number of carbonatoms within a range of 3 to 15 carbon atoms that is represented by R¹¹and R¹² is preferably an unsubstituted linear alkyl group having an oddnumber of carbon atoms within a range of 5 to 15 carbon atoms, morepreferably an unsubstituted linear alkyl group having an odd number ofcarbon atoms within a range of 7 to 13 carbon atoms, and particularlypreferably an unsubstituted linear alkyl group having 9 or 11 carbonatoms.

Each of R¹¹ and R¹² is preferably a linear alkyl group, because then themolecular linearity is improved, and hence carrier mobility can beimproved. In contrast, from the viewpoint of improving solubility in anorganic solvent, each of R¹¹ and R¹² may be a branched alkyl group.

In a case where each of R¹¹ and R¹² is a substituted linear alkyl grouphaving 3 to 15 carbon atoms or a substituted branched alkyl group having3 to 18 carbon atoms, the substituent is not particularly limited.Examples of the substituent include a halogen atom, an alkenyl group(including an ethenyl group, a 1-pentenyl group, a 1-heptanyl group, acycloalkenyl group, a bicycloalkenyl group, and the like), an alkynylgroup (including a 1-pentynyl group, a trimethylsilylethynyl group, atriethylsilylethynyl group, a tri-i-propylsilylethynyl group, a2-p-propylphenylethynyl group, and the like), an aryl group (includingan aryl group having 6 to 20 carbon atoms such as a phenyl group, anaphthyl group, a p-pentylphenyl group, a 3,4-dipentylphenyl group, ap-heptoxyphenyl group, a 3,4-diheptoxyphenyl group, and the like), ahetero ring group (may be referred to as a heterocyclic group as well,including a 2-hexylfuranyl group and the like), a cyano group, ahydroxyl group, a nitro group, an acyl group (including a hexanoylgroup, a benzoyl group, and the like), an alkoxy group (including abutoxy group and the like), an aryloxy group (including a phenoxy groupand the like), a silyloxy group, a heterocyclic oxy group, an acyloxygroup, a carbamoyloxy group, an amino group (including an anilinogroup), an acylamino group, an aminocarbonylamino group (including aureido group), alkoxy- and aryloxycarbonylamino groups, alkyl- and arylsulfonylamino groups, a mercapto group, alkyl- and arylthio groups(including a methylthio group, an octylthio group, and the like), aheterocyclic thio group, a sulfamoyl group, a sulfo group, alkyl- andaryl sulfinyl groups, alkyl- and aryl sulfonyl groups, alkyloxy- andaryloxycarbonyl groups, a carbamoyl group, aryl- and heterocyclic azogroup, an imido group, a phosphino group, a phosphinyl group, aphosphinyloxy group, a phosphinylamino group, a phosphono group, a silylgroup (a ditrimethylsiloxy methylbutoxy group), a hydrazino group, aureido group, a boronic acid group (—B(OH)₂), a phosphate group(—OPO(OH)₂), a sulfate group (—OSO₃H), and other known substituents.

These substituents may further have the substituents described above.

Among these, as substituents that can be adopted, a halogen atom, anaryl group, an alkenyl group, an alkynyl group, a heterocyclic group, analkoxy group, an alkylthio group, an acyloxy group, an aryloxy group,and an alkyloxycarbonyl group are preferable, a fluorine atom, an arylgroup having 6 to 20 carbon atoms, an alkenyl group (preferably a1-alkenyl group) having 2 to 12 carbon atoms, an alkynyl group having 2to 12 carbon atoms, an alkoxy group having 1 to 11 carbon atoms, anacyloxy group, an alkylthio group having 1 to 12 carbon atoms, and analkyloxycarbonyl group are more preferable, a halogen atom, an alkoxygroup, an acyloxy group, and an alkyloxycarbonyl group are particularlypreferable, and a halogen atom and an alkoxy group are most preferable.

In a case where each of R¹¹ and R¹² is an alkyl group substituted with afluorine atom, some of the hydrogen atoms of the alkyl group may besubstituted with a fluorine atom, or all of the hydrogen atoms may besubstituted with a fluorine atom such that a perfluoroalkyl group isformed.

Here, each of R¹¹ and R¹² is preferably an unsubstituted linear orbranched alkyl group.

In a case where each of R¹¹ and R¹² is a substituted linear alkyl grouphaving 3 to 15 carbon atoms, the linear alkyl group is preferably asubstituted linear alkyl group having 3 to 13 carbon atoms, morepreferably a substituted linear alkyl group having 3 to 11 carbon atoms,particularly preferably a substituted linear alkyl group having 5 to 11carbon atoms, and more particularly preferably a substituted linearalkyl group having 7 to 11 carbon atoms.

In a case where each of R¹¹ and R¹² is a substituted branched alkylgroup having 3 to 18 carbon atoms, the branched alkyl group ispreferably a substituted branched alkyl group having 3 to 15 carbonatoms, more preferably a substituted branched alkyl group having 3 to 13carbon atoms, particularly preferably a substituted branched alkyl grouphaving 3 to 11 carbon atoms, and more particularly preferably asubstituted branched alkyl group having 7 to 11 carbon atoms.

In a case where each of R¹¹ and R¹² is a linear or branched alkyl grouphaving a substituent, each of —CH₂— groups not being adjacent to eachother in the linear alkyl group, —CH₂— groups not being adjacent to eachother in the branched alkyl group, a trivalent tertiary carbon atomlinking group, and a tetravalent quaternary carbon atom linking groupmay be independently substituted with other atom linking groups. In thiscase, example of other atom linking groups include —O—, —S—, —CO—,—COO—, —OCO—, —COS—, —SCO—, —NRCO—, —CONR— (R represents a hydrogen atomor an alkyl group having 1 to 6 carbon atoms), and the like.

Here, in R¹¹ and R¹², each of —CH₂— groups not being adjacent to eachother in the linear alkyl group, —CH₂— groups not being adjacent to eachother in the branched alkyl group, a trivalent tertiary carbon atomlinking group, and a tetravalent quaternary carbon atom linking group ispreferably not substituted with other atom linking groups.

In the present invention, each of R¹¹ and R¹² in the compound, which isrepresented by Formula (2) and satisfies the condition A, preferablyindependently has 3 to 30 carbon atoms in total and represents anunsubstituted linear alkyl group having an even number of carbon atomswithin a range of 8 to 10 carbon atoms or an unsubstituted linear alkylgroup having an odd number of carbon atoms within a range of 3 to 15carbon atoms, and an aromatic portion in Formula (2) may be substitutedwith a halogen atom.

In the present invention, each of R¹¹ and R¹² in the compound, which isrepresented by Formula (2) and satisfies the condition A, preferablyindependently has 3 to 30 carbon atoms in total and represents a linearalkyl group having 3 to 15 carbon atoms substituted with a substituentthrough an ether structure or an ester bond.

Examples of the substituent substituted through an ether structure or anester bond include the substituents that can be adopted for R¹¹ and R¹²,and among these, an alkyl group is preferable, and a linear alkyl groupis more preferable. The number of carbon atoms of the substituentsubstituted through an ether structure or an ester bond is preferably 1to 10, more preferably 1 to 5, and particularly preferably 2 to 5.

(Condition B)

In the present invention, the compound represented by Formula (2) morepreferably satisfies the following condition B;

condition B: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent an unsubstituted linear alkyl grouphaving an even number of carbon atoms within a range of 2 to 4 carbonatoms.

(Condition C)

In the present invention, the compound represented by Formula (2) morepreferably satisfies the following condition C;

condition C: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total and represent a substituted alkyl group having 1or 2 carbon atoms.

Among the compounds satisfying the condition C, a compound is preferablein which R¹¹ and R¹² each independently have 3 to 30 carbon atoms intotal and represent an alkyl group having 1 or 2 carbon atomssubstituted with a substituent through an ether structure or an esterbond.

Examples of the substituent substituted through an ether structure or anester bond include the substituents that can be adopted for R¹¹ and R¹².Among these, an alkyl group is preferable, and a linear alkyl group ismore preferable. The number of carbon atoms of the substituentsubstituted through an ether structure or an ester bond is preferably 1to 10, more preferably 1 to 5, and particularly preferably 2 to 5.

(Condition D)

In the present invention, the compound represented by Formula (2) morepreferably satisfies the following condition D;

condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.

Among the compounds satisfying the condition D, a compound is preferablein which R¹¹ and R¹² each independently have 3 to 30 carbon atoms intotal, R¹¹ represents an unsubstituted linear alkyl group, and R¹²represents a substituted or unsubstituted linear or branched alkyl groupdifferent from R¹¹. Particularly, a compound is preferable in which R¹¹and R¹² each independently have 3 to 30 carbon atoms in total andrepresent an unsubstituted linear alkyl group, and R¹¹ and R¹² havedifferent structures.

The total number of carbon atoms that R¹¹ and R¹² each independentlyhave is preferably 3 to 30, more preferably 7 to 30, particularlypreferably 7 to 20, more particularly preferably 7 to 15, even moreparticularly preferably 7 to 11, and still more particularly preferably9 to 11. If the total number of carbon atoms that R¹¹ and R¹² eachindependently have is equal to or greater than the lower limit of theabove range, carrier mobility is improved. If the total number of carbonatoms of R¹¹ and R¹² is equal to or less than the upper limit of theabove range, solubility in an organic solvent is improved.

Specific examples of the compound represented by Formula (2) will beshown below, but the compound represented by Formula (2) that can beused in the present invention is not limited to the following specificexamples. Herein, R¹¹ and R¹² in the following Tables 1 and 2 representR¹¹ and R¹² in Formula (2).

TABLE 1 Compound R¹¹ R¹² Compound 1  n-C₁₀H₂₁ n-C₁₀H₂₁ Compound 2  C₂H₅C₂H₅ Compound 3  n-C₃H₇ n-C₃H₇ Compound 4  n-C₄H₉ n-C₄H₉ Compound 5 n-C₅H₁₁ n-C₅H₁₁ Compound 6  n-C₆H₁₃ n-C₆H₁₃ Compound 7  n-C₇H₁₅ n-C₇H₁₅Compound 8  n-C₈H₁₇ n-C₈H₁₇ Compound 9  n-C₉H₁₉ n-C₉H₁₉ Compound 10n-C₁₂H₂₅ n-C₁₂H₂₅ Compound 11

Compound 12

Compound 13

Compound 14 (CH₂)₄F (CH₂)₄F Compound 15 (CH₂)₃Ph (CH₂)₃Ph Compound 16

Compound 17

Compound 18

Compound 19

Compound 20

Compound 21

Compound 22

Compound 23

Compound 24

TABLE 2 Compound R¹¹ R¹² Compound C₂H₅ n-C₄H₉ 25 Compound C₂H₅ n-C₆H₁₃26 Compound n-C₃H₇ n-C₆H₁₃ 27 Compound n-C₃H₇ n-C₄H₉ 28 Compound n-C₄H₉n-C₅H₁₁ 29 Compound n-C₄H₉ n-C₆H₁₃ 30 Compound n-C₄H₉ n-C₈H₁₇ 31Compound n-C₄H₉ n-C₁₂H₂₅ 32 Compound n-C₅H₁₁ n-C₆H₁₃ 33 Compound 34n-C₈H₁₇

Compound 35 n-C₈H₁₇

Compound n-C₁₂H₂₅ (CH₂)₄F 36 Compound n-C₈H₁₇ (CH₂)₃Ph 37 Compound 38n-C₄H₉

Compound 39 n-C₁₂H₂₅

Compound 40

The molecular weight of the compound represented by Formula (2) ispreferably equal to or less than 3,000, more preferably equal to or lessthan 2,000, even more preferably equal to or less than 1,000, andparticularly preferably equal to or less than 850. It is preferable thatthe molecular weight is equal to or less than the above upper limit,because then the solubility of the compound in a solvent can beimproved.

From the viewpoint of film quality stability of the film, the molecularweight is preferably equal to or greater than 250, more preferably equalto or greater than 300, and even more preferably equal to or greaterthan 350.

The compound represented by Formula (2) can be synthesized withreference to the method described in Tetrahedron 66 (2010) 8778-8784 orthe method described in examples which will be described later.

For synthesizing the compound represented by Formula (2), any ofreaction conditions may be used. As a reaction solvent, any of solventsmay be used. Furthermore, in order to accelerate a ring-formingreaction, an acid or a base is preferably used, and an acid isparticularly preferably used. Although optimal reaction conditions varywith the structure of the intended compound, they can be set withreference to the specific reaction conditions described in theaforementioned documents or the method described in examples which willbe described later.

A synthetic intermediate having various substituents can be synthesizedusing known reactions in combination. Furthermore, various substituentsmay be introduced into the intermediate at any stage. After theintermediate is synthesized, it is preferable to purify the intermediateby column chromatography, recrystallization, or the like and thenfurther purify it by sublimation. By the sublimation purification, it ispossible to separate organic impurities and to effectively remove aninorganic salt, a residual solvent, and the like.

<Solvent>

In a case where a film is formed on a substrate by using a solutionprocess, by using a coating solution, which is obtained by dissolving ordispersing a material for forming a layer in an appropriate organicsolvent (for example, a hydrocarbon-based solvent such as hexane,octane, decane, toluene, xylene, mesitylene, ethylbenzene, amylbenzene,decalin, 1-methylnaphthalene, 1-ethylnaphthalene,1,6-dimethylnaphthalene, or tetralin, a ketone-based solvent such asacetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,acetophenone, propiophenone, butyrophenone, α-tetralone, or β-tetralone,a halogenated hydrocarbon-based solvent such as dichloroethane,chloroform, tetrachloromethane, dichloroethane, trichloroethane,tetrachloroethane, chlorobenzene, 1,2-dichlorobenzene,1,2,4-trichlorobenzene, chlorotoluene, or 1-fluoronaphthalene, aheterocyclic solvent such as pyridine, picoline, quinoline, thiophene,3-butylthiophene, or thieno[2,3-b]thiophene, a halogenated heterocyclicsolvent such as 2-chlorothiophene, 3-chlorothiophene,2,5-dichlorothiophene, 3,4-dichlorothiophene, 2-bromothiophene,3-bromothiophene, 2,3-dibromothiophene, 2,4-dibromothiophene,2,5-dibromothiophene, 3,4-dibromothiophene, or3,4-dichloro-1,2,5-thiadiazole, an ester-based solvent such as ethylacetate, butyl acetate, amyl acetate, 2-ethylhexyl acetate,γ-butyrolactone, or phenyl acetate, an alcohol-based solvent such asmethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, methylcellosolve, ethyl cellosolve, or ethylene glycol, an ether-based solventsuch as dibutyl ether, tetrahydrofuran, dioxane, dimethoxyethane,anisole, ethoxybenzene, propoxybenzene, isopropoxybenzene,butoxybenzene, 2-methylanisole, 3-methylanisole, 4-methylanisole,4-ethylanisole, dimethylanisole (any of 2,3-, 2,4-, 2,5-, 2,6-, 3,4-,3,5-, and 3,6-dimethylanisoles), or 1,4-benzodioxane,2,3-dihydrobenzofuran, phthalan, chroman, or isochroman, anamide/imide-based solvent such as N,N-dimethylformamide,N,N-dimethylacetamide, 1-methyl-2-pyrrolidone,1-methyl-2-imidazolidinone, or 1,3-dimethyl-2-imidazolidinone, asulfoxide-based solvent such as dimethylsulfoxide, a phosphoric acidester-based solvent such as trimethyl phosphate, a nitrile-based solventsuch as acetonitrile or benzonitrile, a nitro-based solvent such asnitromethane or nitrobenzene) and/or water, a film can be formed byvarious coating methods. One kind of solvent may be used singly, orplural kinds thereof may be used in combination. Among these, ahydrocarbon-based solvent, a ketone-based solvent, a halogenatedhydrocarbon-based solvent, a heterocyclic solvent, a halogenatedheterocyclic solvent, or an ether-based solvent is preferable, toluene,xylene, mesitylene, amylbenzene, tetralin, acetophenone, propiophenone,butyrophenone, α-tetralone, dichlorobenzene, anisole, ethoxybenzene,propoxybenzene, isopropoxybenzene, butoxybenzene, 2-methylanisole,3-methylanisole, 4-methylanisole, 2,3-dihydrobenzofuran, phthalan,chroman, isochroman 1-fluoronaphthalene, 3-chlorothiophene, and2,5-dibromothiophene are more preferable, and toluene, xylene, tetralin,acetophenone, propiophenone, butyrophenone, α-tetralone, anisole,ethoxybenzene, propoxybenzene, butoxybenzene, 2-methylanisole,3-methylanisole, 4-methylanisole, 2,3-dihydrobenzofuran, phthalan,chroman, isochroman, 1-fluoronaphthalene, 3-chlorothiophene, and2,5-dibromothiophene are particularly preferable.

In the first aspect of the coating solution for a non-light-emittingorganic semiconductor device of the present invention, among thesesolvents, a solvent having a boiling point of equal to or higher than100° C. is used. In the first aspect of the coating solution for anon-light-emitting organic semiconductor device of the presentinvention, the coating solution contains a solvent having a boilingpoint of equal to or higher than 100° C., and this results in anadvantage that excellent film quality and crystals with a large area canbe obtained. The coating solution of the first aspect is suitably usedin a method for manufacturing an organic semiconductor film of thepresent invention

Furthermore, in the second aspect of the coating solution for anon-light-emitting organic semiconductor device of the presentinvention, it is preferable to use a solvent having a boiling point ofequal to or higher than 100° C. from the same standpoint as describedabove.

From the viewpoint described above, the boiling point of the solventhaving a boiling point of equal to or higher than 100° C. is preferablyequal to or higher than 150° C., more preferably equal to or higher than175° C., and particularly preferably equal to or higher than 200° C.

In addition, from the viewpoint of environmental load and toxicity tohuman beings, the solvent having a boiling point of equal to or higherthan 100° C. is preferably a non-halogen-based solvent.

The concentration of the compound represented by Formula (2) in thecoating solution is preferably 0.005% to 5% by mass, more preferably0.01% to 3% by mass, and particularly preferably 0.1% to 2% by mass. Ifthe concentration is within the above range, a film with arbitrarythickness is easily formed. Furthermore, it is particularly preferablethat the concentration of the compound represented by Formula (2) in thecoating solution for a non-light-emitting organic semiconductor deviceis equal to or greater than 0.4% by mass, because then a coating filmcomposed of large-sized crystals is easily formed. Although Tetrahedron66 (2010) 8778-8784 describes a low-concentration solution for measuringoxidation-reduction potential or emission/absorption, from the viewpointdescribed above, it is preferable that the concentration of the coatingsolution for a non-light-emitting organic semiconductor device is high.

For the coating solution for a non-light-emitting organic semiconductordevice of the present invention, an aspect is also preferable in whichthe coating solution contains the compound represented by Formula (2)but does not contain a polymer binder.

Furthermore, the coating solution for a non-light-emitting organicsemiconductor device of the present invention may contain the compoundrepresented by Formula (2) and a polymer binder. In this case, by usinga coating solution obtained by dissolving or dispersing a material,which will be formed into a layer, and a polymer binder in anappropriate solvent described above, a film can be formed by variouscoating methods. The polymer binder can be selected from those whichwill be described later.

From the viewpoint of the film quality uniformity of the coating film tobe formed, the coating solution for a non-light-emitting organicsemiconductor device preferably contains a polymer.

The coating solution for a non-light-emitting organic semiconductordevice may contain only one kind of compound represented by Formula (2)or contain two or more kinds thereof. From the viewpoint of the storagestability (inhibition of crystal precipitation during storage) of thecoating solution, the coating solution preferably contains two or morekinds of compound represented by Formula (2).

From the viewpoint of the suitability for various printing methods, thecoating solution for a non-light-emitting organic semiconductor devicepreferably has a viscosity of equal to or greater than 10 mPa·s.

The coating solution for a non-light-emitting organic semiconductordevice may contain additives other than a polymer binder, such as asurfactant, an antioxidant, a crystallization control agent, and acrystal orientation control agent.

Examples of the surfactant are not particularly limited and includenonionic surfactants such as polyoxyethylene alkyl ethers,polyoxyethylene alkyl allyl ethers, polyoxyethylene-polyoxypropyleneblock copolymers, sorbitan fatty acid esters, and a polyoxyethylenesorbitan fatty acid ester; fluorine-based surfactants such as MEGAFACEF171 and F176 (manufactured by DIC Corporation), FLUORAD FC430(manufactured by Sumitomo 3M Ltd.), SURFYNOL E1004 (manufactured byASAHI GLASS CO., LTD.), and PF656 and PF6320 manufactured by OMNOVASolutions Inc.; and organosiloxane polymers such as polysiloxanepolymers KP-341 (manufactured by Shin-Etsu Chemical Co., Ltd.), KF-410(manufactured by Shin-Etsu Chemical Co., Ltd.), KF-412 (manufactured byShin-Etsu Chemical Co., Ltd.), KF-96-100cs (manufactured by Shin-EtsuChemical Co., Ltd.), BYK-322 (manufactured by BYK Additives &Instruments), and BYK-323 (manufactured by BYK Additives & Instruments).

The content of the surfactant in the coating solution is preferablyabout 0.001% to 1% by mass.

Examples of the antioxidant include a phenol-based antioxidant, aphosphorus-based antioxidant, a sulfur-based antioxidant, and the like.

Specific examples of the phenol-based antioxidant include2,6-di-t-butyl-4-methylphenol,n-octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate,tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane,tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate,4,4′-butylidenebis-(3-methyl-6-t-butylphenol), triethylene glycolbis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate], and 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane.

Examples of commercially available products of the phenol-basedantioxidant include IRGANOX 1010, IRGANOX 1035, IRGANOX 1076, IRGANOX1135, IRGANOX 245, IRGANOX 259, IRGANOX 295, and IRGANOX 3114 (allmanufactured by BASF SE), ADEKA STAB AO-20, ADEKA STAB AO-30, ADEKA STABAO-40, ADEKA STAB AO-50, ADEKA STAB AO-60, ADEKA STAB AO-70, ADEKA STABAO-80, ADEKA STAB AO-90, and ADEKA STAB AO-330 (all manufactured byADEKA Corporation), SUMILIZER BHT, SUMILIZER BP-101, SUMILIZER GA-80,SUMILIZER MDP-S, SUMILIZER BBM-S, SUMILIZER GM, SUMILIZER GS(F), andSUMILIZER GP (all manufactured by Sumitomo Chemical Co., Ltd.), HOSTANOX010, HOSTANOX 016, HOSTANOX 014, and HOSTANOX 03 (all manufactured byCLARIANT), ANTAGE BHT, ANTAGE W-300, ANTAGE W-400, and ANTAGE W-500 (allmanufactured by Kawaguchi Chemical Industry Co., LTD.), SEENOX 224M andSEENOX 326 M (all manufactured by SHIPRO KASEI KAISHA, LTD.), YOSHINOXBHT, YOSHINOX BB, TOMINOX TT, and TOMINOX 917 (all manufactured byYOSHITOMI PHARMACEUTICAL INDUSTRIES, LTD.), TTHP (manufactured by TORAYINDUSTRIES, INC.), and the like.

Specific examples of the phosphorus-based antioxidant includetrisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl)phosphite,distearyl pentaerythritol diphosphite,bis(2,4-di-t-butylphenyl)pentaerythritol phosphite,bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol phosphite,2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite,tetrakis(2,4-di-t-butylphenyl)-4,4-biphenylene-di-phosphonite, and thelike. Examples of commercially available products of thephosphorus-based antioxidant include ADEKA STAB 1178 (manufactured byADEKA Corporation), SUMILIZER TNP (manufactured by Sumitomo ChemicalCo., Ltd.), JP-135 (manufactured by JOHOKU CHEMICAL CO., LTD), ADEKASTAB 2112 (manufactured by ADEKA Corporation), JPP-2000 (manufactured byJOHOKU CHEMICAL CO., LTD), WESTON 618 (manufactured by GeneralElectric), ADEKA STAB PEP-24G (manufactured by ADEKA Corporation), ADEKASTAB PEP-36 (manufactured by ADEKA Corporation), ADEKA STAB HP-10(manufactured by ADEKA Corporation), SANDSTAB P-EPQ (manufactured bySandoz), PHOSPHITE 168 (manufactured by Ciba Specialty Chemicals, Inc.),and the like.

Specific examples of the sulfur-based antioxidant includedilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate,distearyl-3,3′-thiodipropionate, pentaerythritoltetrakis(3-laurylthiopropionate), and the like. Examples of commerciallyavailable products of the sulfur-based antioxidant include SUMILIZER TPL(manufactured by Sumitomo Chemical Co., Ltd.), YOSHINOX DLTP(manufactured by YOSHITOMI PHARMACEUTICAL INDUSTRIES, LTD.), ANTIOX L(manufactured by NOF CORPORATION), SUMILIZER TPM (manufactured bySumitomo Chemical Co., Ltd.), YOSHINOX DMTP (manufactured by YOSHITOMIPHARMACEUTICAL INDUSTRIES, LTD.), ANTIOX M (manufactured by NOFCORPORATION), SUMILIZER TPS (manufactured by Sumitomo Chemical Co.,Ltd.), YOSHINOX DSTP (manufactured by YOSHITOMI PHARMACEUTICALINDUSTRIES, LTD.), ANTIOX S (manufactured by NOF CORPORATION), ADEKASTAB AO-412S (manufactured by ADEKA Corporation), SEENOX 412S(manufactured by SHIPRO KASEI KAISHA, LTD.), SUMILIZER TDP (manufacturedby Sumitomo Chemical Co., Ltd.), and the like.

The content of the antioxidant in the coating solution is preferablyabout 0.01% to 5% by mass.

<Structure of Organic Transistor>

The first aspect of the organic transistor of the present inventioncontains the compound represented by Formula (2) in a semiconductoractive layer.

The second aspect of the organic transistor of the present inventioncontains the compound of the present invention in a semiconductor activelayer.

That is, the organic transistor of the present invention has asemiconductor active layer containing the compound represented byFormula (2).

The organic transistor of the present invention may further have layersother than the semiconductor active layer.

The organic transistor of the present invention is preferably used as anorganic field effect transistor (FET), and is more preferably used as aninsulated gate-type FET in which the gate is insulated from channels.

Hereinafter, preferred structural aspects of the organic transistor ofthe present invention will be specifically described by using drawings,but the present invention is not limited to the aspects.

(Lamination Structure)

The lamination structure of an organic field effect transistor is notparticularly limited, and various known structures can be adopted.

For example, the organic transistor of the present invention can adopt astructure (bottom gate/top contact type) in which an electrode, aninsulator layer, a semiconductor active layer (organic semiconductorlayer), and two electrodes are arranged in this order on the uppersurface of a substrate which is a lower most layer. In this structure,the electrode on the upper surface of the substrate as the lower mostlayer is provided in a portion of the substrate, and the insulator layeris so disposed that it comes into contact with the substrate in aportion other than the electrode. The two electrodes provided on theupper surface of the semiconductor active layer are arranged in a stateof being separated from each other.

FIG. 1 shows the constitution of a bottom gate/top contact-type element.FIG. 1 is a schematic view showing a section of an exemplary structureof the organic transistor of the present invention. In the organictransistor shown in FIG. 1, a substrate 11 is disposed as a lower mostlayer, an electrode 12 is provided in a portion of the upper surfacethereof, and an insulator layer 13 is provided such that it covers theelectrode 12 and contacts the substrate 11 in a portion other than theelectrode 12. On the upper surface of the insulator layer 13, asemiconductor active layer 14 is provided, and in a portion of the uppersurface thereof, two electrodes 15 a and 15 b are arranged in a state ofbeing separated from each other.

In the organic transistor shown in FIG. 1, the electrode 12 is a gate,and the electrode 15 a and the electrode 15 b are a drain and a sourcerespectively. The organic transistor shown in FIG. 1 is an insulatedgate-type FET in which a channel as a path of electric currents betweenthe drain and the source is insulated from the gate.

As an example of the structure of the organic transistor of the presentinvention, a bottom gate/bottom contact-type element can be exemplified.

FIG. 2 shows the constitution of the bottom gate/bottom contact-typeelement. FIG. 2 is a schematic view showing a section of the structureof an organic transistor manufactured as a substrate for measuring FETcharacteristics in examples of the present invention. In the organictransistor shown in FIG. 2, a substrate 31 is disposed as a lower mostlayer, an electrode 32 is provided in a portion of the upper surfacethereof, and an insulator layer 33 is provided such that it covers theelectrode 32 and comes into contact with the substrate 31 in a portionother than the electrode 32. Furthermore, a semiconductor active layer35 is provided on the upper surface of the insulator layer 33, andelectrodes 34 a and 34 b are in a lower portion of the semiconductoractive layer 35.

In the organic transistor shown in FIG. 2, the electrode 32 is a gate,and the electrode 34 a and the electrode 34 b are a drain and a sourcerespectively. The organic transistor shown in FIG. 2 is an insulatedgate-type FET in which a channel as a path of electric currents betweenthe drain and the source is insulated from the gate.

As the structure of the organic transistor of the present invention, atop gate/top contact-type element in which an insulator and a gateelectrode are in the upper portion of a semiconductor active layer or atop gate/bottom contact-type element can also be preferably used.

(Thickness)

In a case where the organic transistor of the present invention needs tobe a thinner transistor, the total thickness of the transistor ispreferably, for example, 0.1 μm to 0.5 μm.

(Sealing)

In order to improve the preservation stability of the organic transistorelement by blocking the organic transistor element from the atmosphereor moisture, the entirety of the organic transistor element may besealed with a metal sealing can, glass, an inorganic material such assilicon nitride, a polymer material such as perylene, a low-molecularweight material, or the like.

Hereinafter, preferred aspects of the respective layers of the organictransistor of the present invention will be described, but the presentinvention is not limited to the aspects.

<Substrate>

(Material)

The organic transistor of the present invention preferably includes asubstrate.

The material of the substrate is not particularly limited, and knownmaterials can be used. Examples of the material include a polyester filmsuch as polyethylene naphthalate (PEN) or polyethylene terephthalate(PET), a cycloolefin polymer film, a polycarbonate film, atriacetylcellulose (TAC) film, a polyimide film, a material obtained bybonding these polymer films to extremely thin glass, ceramics, silicon,quartz, glass, and the like. Among these, silicon is preferable.

<Electrode>

(Material)

The organic transistor of the present invention preferably includes anelectrode.

As the material constituting the electrode, known conductive materialssuch as a metal material like Cr, Al, Ta, Mo, Nb, Cu, Ag, Au, Pt, Pd,In, Ni, or Nd, an alloy material of these, a carbon material, and aconductive polymer can be used without particular limitation.

(Thickness)

The thickness of the electrode is not particularly limited, but ispreferably 10 nm to 50 nm.

A gate width (or a channel width) W and a gate length (or a channellength) L are not particularly limited. However, a ratio of W/L ispreferably equal to or greater than 10, and more preferably equal to orgreater than 20.

<Acceptor>

(Material)

The organic transistor of the present invention may include an acceptorfor accelerating injection of carriers. Preferred examples of thematerial include known2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and thelike.

(Thickness)

The thickness of the acceptor is not particularly limited and ispreferably equal to or less than 5 nm.

<Insulating Layer>

(Material)

The material constituting the insulating layer is not particularlylimited as long as a necessary insulating effect is obtained. Examplesof the material include silicon dioxide, silicon nitride, a fluorinepolymer-based insulating material such as polytetrafluoroethylene (PTFE)or CYTOP, a polyester insulating material, a polycarbonate insulatingmaterial, an acryl polymer-based insulating material, an epoxyresin-based insulating material, a polyimide insulating material, apolyvinyl phenol resin-based insulating material, a poly p-xylyleneresin-based insulating material, and the like.

A surface treatment may be performed on the upper surface of theinsulating layer. For example, it is possible to preferably use aninsulating layer in which the silicon dioxide surface thereof issubjected to the surface treatment by being coated withhexamethyldisilazane (HMDS), octadecyltrichlorosilane (OTS), orβ-phenethyltrimethoxysilane.

(Thickness)

The thickness of the insulating layer is not particularly limited.However, in a case where the film needs to be thinned, the thickness ofthe insulating layer is preferably 10 nm to 500 nm, more preferably 20nm to 200 nm, and particularly preferably 50 nm to 200 nm.

<Semiconductor Active Layer>

(Material)

The organic transistor of the present invention contains the compoundrepresented by Formula (2) in the semiconductor active layer.

The semiconductor active layer may be a layer further containing apolymer binder (referred to as a polymer or a binder as well) inaddition to the compound represented by Formula (2). Furthermore, thesemiconductor active layer may contain a residual solvent used at thetime of forming a film.

The content of the polymer binder in the semiconductor active layer isnot particularly limited. The content of the polymer binder used ispreferably within a range of 0% to 95% by mass, more preferably within arange of 10% to 90% by mass, even more preferably within a range of 20%to 80% by mass, and particularly preferably within a range of 30% to 70%by mass.

(Thickness)

The thickness of the semiconductor active layer is not particularlylimited. In a case where the film needs to be thinned, the thickness ofthe semiconductor active layer is preferably 10 nm to 400 nm, morepreferably 10 nm to 200 nm, and particularly preferably 10 nm to 100 nm.

[Method for Manufacturing Organic Transistor]

A method for manufacturing an organic transistor of the presentinvention includes a step of preparing a semiconductor active layer bycoating a substrate with a coating solution for a non-light-emittingorganic semiconductor device of the present invention and drying thecoating solution.

The method for manufacturing an organic transistor of the presentinvention may or may not include a method for manufacturing an organicsemiconductor film of the present invention that will be describedlater.

First, general methods in the method for manufacturing an organictransistor of the present invention will be described.

(Film Forming Method)

In the method for manufacturing an organic transistor of the presentinvention, the compound of the present invention or the compoundrepresented by Formula (2) may be formed into a film on a substrate byany method.

At the time of forming the film, the substrate may be heated or cooled.By varying the temperature of the substrate, it is possible to controlthe film quality or the packing of molecules in the film. Thetemperature of the substrate is not particularly limited. Thetemperature is preferably between 0° C. to 200° C., more preferablybetween 15° C. to 120° C., and particularly preferably between 20° C. to100° C.

The compound of the present invention or the compound represented byFormula (2) can be formed into a film on a substrate by a vacuum processor a solution process, and both of the processes are preferable.

Specific examples of the film forming method by a vacuum process includea physical vapor deposition method such as a vacuum vapor depositionmethod, a sputtering method, an ion plating method, or a molecular beamepitaxy (MBE) method and a chemical vapor deposition (CVD) method suchas plasma polymerization, and it is particularly preferable to use avacuum vapor deposition method.

Herein, the film forming method by a solution process refers to a methodof dissolving an organic compound in a solvent which can dissolve thecompound and forming a film by using the solution. Specifically, it ispossible to use general methods like a coating method such as a castingmethod, a dip coating method, a die coater method, a roll coater method,a bar coater method, or a spin coating method, various printing methodssuch as an ink jet method, a screen printing method, a gravure printingmethod, a flexographic printing method, an offset printing method, or amicro-contact printing method, and a Langmuir-Blodgett (LB) method. Itis particularly preferable to use a casting method, a spin coatingmethod, an ink jet method, a gravure printing method, a flexographicprinting method, an offset printing method, or a micro-contact printingmethod.

The organic semiconductor film for a non-light-emitting organicsemiconductor device of the present invention is preferably prepared bya solution coating method. In a case where the organic semiconductorfilm for a non-light-emitting organic semiconductor device of thepresent invention contains a polymer binder, it is preferable to preparea coating solution by dissolving or dispersing a material, which will beformed into a layer, and a polymer binder in an appropriate solvent andto form the organic semiconductor film by various coating methods.

Next, as a more preferred aspect in the method for manufacturing anorganic transistor of the present invention, a method including themethod for manufacturing an organic semiconductor film of the presentinvention will be described.

[Method for Manufacturing Organic Semiconductor Film]

In a first aspect of the method for manufacturing an organicsemiconductor film of the present invention, in a state where a distancebetween a substrate A and a member B not being fixed to the substrate Ais kept constant or in a state where the substrate A and the member Bare caused to remain in contact with each other, a coating solutioncontaining a compound represented by the following Formula (2) and asolvent having a boiling point of equal to or higher than 100° C. isdropped onto a portion within the surface of the substrate A such thatthe coating solution contacts both of the substrate A and the member B,and the dropped coating solution is slowly dried, such that crystals ofthe compound represented by Formula (2) are precipitated and asemiconductor active layer is formed; here, as long as the distancebetween the substrate A and the member B is kept constant or as long asthe substrate A and the member B are caused to remain in contact witheach other, the positional relationship between the substrate A and themember B may be maintained or changed when the coating solution isdropped or dried;

in Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and an aromatic portion in Formula (2)may be substituted with a halogen atom.

In a second aspect of the method for manufacturing an organicsemiconductor film of the present invention, in a state where a distancebetween a substrate A and a member B not being fixed to the substrate Ais kept constant or in a state where the substrate A and the member Bare caused to remain in contact with each other, a coating solutionprepared by dissolving the compound of the present invention in asolvent is dropped onto a portion within the surface of the substrate Asuch that the coating solution contacts both of the substrate A and themember B, and the dropped coating solution is slowly dried, such thatcrystals of the compound of the present invention are precipitated and asemiconductor active layer is formed; here, as long as the distancebetween the substrate A and the member B is kept constant or as long asthe substrate A and the member B are caused to remain in contact witheach other, the positional relationship between the substrate A and themember B may be maintained or changed when the coating solution isdropped or dried.

Hereinafter, the first and second aspects of the method formanufacturing an organic semiconductor film of the present inventionwill be comprehensively described.

The preferred aspects of the method for manufacturing an organicsemiconductor film of the present invention will be described based ondrawings.

FIGS. 3A to 3C are schematic views showing an example of the method formanufacturing an organic semiconductor film of the present invention.

FIG. 3A shows a state where the coating solution (reference 41) has notyet been dropped onto the substrate A (reference 42). In this state, thedistance between the substrate A (reference 42) and the member B(reference 43) not being fixed to the substrate A (reference 42) is keptconstant.

FIG. 3B shows a state where the coating solution (reference 41) is thendropped onto a portion within the surface of the substrate A (reference42) such that the coating solution contacts both of the substrate A(reference 42) and the member B (reference 43).

FIG. 3C is a schematic view showing an aspect in which the droppedcoating solution (reference 41) is then slowly dried in a state wherethe positional relationship between the substrate A (reference 42) andthe member B (reference 43) is maintained. The coating solution(reference 41) starts to be dried from both edges where the filmthickness is small and is crystallized, and in this way, large-sizedcrystals can be obtained.

FIGS. 4A to 4C are schematic views showing another example of the methodfor manufacturing an organic semiconductor film of the presentinvention.

FIG. 4A shows a state where the coating solution (reference 41) has notyet been dropped onto the substrate A (reference 42). In this state, thesubstrate A (reference 42) and the member B (reference 43) are caused toremain in contact with each other.

FIG. 4B1 shows a state where the coating solution (reference 41) is thendropped onto a portion within the surface of the substrate A (reference42) such that the coating solution contacts both of the substrate A(reference 42) and the member B (reference 43). It is FIG. 4B2 that isobtained when FIG. 4B 1 is seen in a vertical direction (Y-axisdirection). As is evident from FIG. 4B2, the coating solution (reference41) is dropped on a portion within the surface of the substrate A(reference 42).

FIG. 4C is a schematic view showing an aspect in which the droppedcoating solution (reference 41) is then slowly dried in a state wherethe positional relationship between the substrate A (reference 42) andthe member B (reference 43) is maintained. The coating solution(reference 41) starts to be dried from both edges where the filmthickness is small and is crystallized, and in this way, large-sizedcrystals can be obtained.

Comparing the aspect shown in FIGS. 3A to 3C with the aspect shown inFIGS. 4A to 4C, the aspect shown in FIGS. 4A to 4C in which thesubstrate A (reference 42) and the member B (reference 43) are caused toremain in contact with each other is preferable, because in this aspect,the film quality is excellent, a holding mechanism is not necessary, andthe distance between the member B (reference 43) and the substrate A(reference 42) can be accurately maintained.

FIGS. 5A to 5C are schematic vies showing another example of the methodfor manufacturing an organic semiconductor film of the presentinvention.

FIG. 5A shows a state where the coating solution (reference 41) has notyet been dropped onto the substrate A (reference 42). In this state, thesubstrate A (reference 42) and the member B (reference 43) are caused toremain in contact with each other.

FIG. 5B shows a state where the coating solution (reference 41) is thendropped onto a portion within the surface of the substrate A (reference42) such that the coating solution contacts both of the substrate A(reference 42) and the member B (reference 43).

FIG. 5C is a schematic view showing an aspect in which the droppedcoating solution is then slowly dried by changing the positionalrelationship between the substrate A (reference 42) and the member B(reference 43).

In the method for manufacturing an organic semiconductor film of thepresent invention, as long as the state where the distance between thesubstrate A and the member B is kept constant or as long as thesubstrate A and the member B are caused to remain in contact with eachother, at the time when the coating solution is dropped or dried, thepositional relationship between the substrate A and the member B may bemaintained or changed. As shown in FIG. 5C, by changing the positionalrelationship between the substrate A (reference 42) and the member B(reference 43) in the −X direction on the coordinates, the coatingsolution (reference 41) starts to be dried from the edge (+X directionon the coordinates) far away from the member B (reference 43) and iscrystallized, and in this way, large-sized crystals can be obtained.

Comparing the aspect shown in FIGS. 5A to 5C with the aspect shown inFIGS. 4A to 4C, the aspect shown in FIGS. 4A to 4C is preferable becausein this aspect, the film quality is excellent, and large-sized crystalsare easily obtained.

Examples of the substrate A used in the method for manufacturing anorganic semiconductor film of the present invention include those usedas a substrate of the organic transistor of the present invention. Asthe substrate A, a substrate in which an insulating layer is formed onthe substrate of the organic transistor of the present invention ispreferable.

The member B used in the method for manufacturing an organicsemiconductor film of the present invention is not particularly limited.The material of the member B is preferably glass; quartz; silicon;Teflon (registered trademark); or plastic such as polyethylene orpolypropylene, and more preferably glass.

The size of the member B (reference 43) (for example, the length of themember B (reference 43) in the X-axis direction and the Y-axis directionin FIG. 4B2) is not particularly limited. The lower limit of the lengthof one side of the member B (reference 43) is preferably equal to orgreater than 0.1% of the length of one side of the substrate A(reference 42), more preferably equal to or greater than 1% of thelength one side of the substrate A, particularly preferably equal to orgreater than 10% of the length of one side of the substrate A, and moreparticularly preferably equal to or greater than 20% of the length ofone side of the substrate A. The upper limit of the length of one sideof the member B (reference 43) is preferably equal to or less than 80%of the length of one side of the substrate A (reference 42), morepreferably equal to or less than 70% of the length of one side of thesubstrate A, and particularly preferably equal to or less than 50% ofthe length of one side of the substrate A.

The height of the member B (reference 43) (for example, the length ofthe member B (reference 43) in the Z-axis direction in FIG. 4B1 is notparticularly limited. The height of the member B (reference 43) ispreferably 1 mm to 50 mm, and more preferably 5 mm to 20 mm.

FIG. 6 is a schematic view of the substrate A and the member B. In FIG.6, d indicates the length of the member B in the x-axis direction inFIG. 4B2; w indicates the length of the member B in the y-axis directionin FIG. 4B2; and h indicates the length of the member B in the z-axisdirection in FIG. 4B1. h/d in the member B shown in FIG. 6 is preferably0.01 to 10, and more preferably 0.1 to 5, because then the member B doesnot collapse. w/d is preferably 1 to 1,000, and more preferably 5 to100, because then the region in which crystals are formed widens.

(Film Forming Method)

In the method for manufacturing an organic semiconductor film of thepresent invention, at the time of forming a film, the substrate may beheated or cooled. By varying the temperature of the substrate, it ispossible to control the film quality or the packing of molecules in thefilm. The temperature of the substrate is not particularly limited.However, it is preferably between 0° C. to 200° C., more preferablybetween 15° C. to 100° C., and particularly preferably between 20° C. to95° C.

When the compound of the present invention is formed into a film on thesubstrate, a solution process is used for forming the film.

Herein, the film forming method by a solution process refers to a methodof dissolving an organic compound in a solvent which can dissolve thecompound and forming a film by using the solution. Specifically, it ispossible to use general methods like various printing methods such as adrop casting method, an ink jet method, a screen printing method, agravure printing method, a flexographic printing method, an offsetprinting method, and a micro-contact printing method. Among these, anink jet method, a gravure printing method, a flexographic printingmethod, an offset printing method, and a micro-contact printing methodare preferably used, and a flexographic printing method, a micro-contactprinting method, and an ink jet method are particularly preferably used.

In the method for manufacturing an organic semiconductor film of thepresent invention, the coating solution is dropped onto a portion withinthe surface of the substrate A such that the coating solution contactsboth of the substrate A and the member B.

At the time of dropping the coating solution, it is preferable to drop asingle drop of the coating solution or to drop the coating solution dropby drop in a case where two or more drops of the coating solution aredropped, because then a portion in which a film of the coating solutionhaving a small thickness is easily formed on the substrate A, and it iseasy to accelerate drying of the coating solution from edge.

In a case where the coating solution is dropped, the volume of a singledrop of the coating solution is preferably 0.01 ml to 0.2 ml, and morepreferably 0.02 ml to 0.1 ml.

By dropping the coating solution onto a portion within the surface ofthe substrate A such that the coating solution contacts both of thesubstrate A and the member B, it is possible to reduce the filmthickness at the edge of the coating solution.

The contact angle between the coating solution and the substrate A ispreferably 0° to 90°, and more preferably 10° to 80°.

The coating solution and the member B preferably form a meniscus, andmore preferably form a concave meniscus from the viewpoint of the filmquality.

Usually, in order to form a film by a solution process, the materialneeds to dissolve in the solvent exemplified above, but simplydissolving in a solvent is not good enough. Generally, even the materialformed into a film by a vacuum process can dissolve in a solvent to someextent. The solution process includes a step of coating a substrate witha material by dissolving the material in a solvent and then forming afilm by evaporating the solvent, and many of the materials not beingsuitable for being formed into a film by the solution process have highcrystallinity. Therefore, the material is inappropriately crystallized(aggregated) in the aforementioned step, and hence it is difficult toform an excellent film. This problem has been considered in the relatedart. In contrast, according to the method for manufacturing an organicsemiconductor film of the present invention, it is possible to form anorganic semiconductor film in a state of causing the precipitation ofcrystals.

(Drying)

In the method for manufacturing an organic semiconductor film of thepresent invention, the dropped coating solution is slowly dried so as tocause the precipitation of crystals of the compound of the presentinvention or the compound represented by Formula (2), thereby forming asemiconductor active layer.

From the viewpoint of the film quality, it is preferable that thecoating solution is air-dried on the heated substrate A and then driedunder reduced pressure.

The temperature of the substrate A at the time of air drying ispreferably 20° C. to 100° C., and more preferably 50° C. to 80° C.

The air drying is preferably performed for 0.5 hours to 20 hours, andmore preferably performed for 1 hour to 10 hours.

The temperature at the time of drying under reduced pressure ispreferably 20° C. to 100° C., and more preferably 40° C. to 80° C.

The drying under reduced pressure is preferably performed for 1 hour to20 hours, and more preferably performed for 2 hours to 10 hours.

The pressure at the time of drying under reduced pressure is preferably10⁻⁶ Pa to 10⁻² Pa, and more preferably 10⁻⁵ Pa to 10⁻³ Pa.

In the method for manufacturing an organic semiconductor film of thepresent invention, crystals of the compound of the present invention orthe compound represented by Formula (2) are precipitated. Whether or notthe crystals have been precipitated can be checked by observation usinga polarizing microscope.

[Organic Semiconductor Material for Non-Light-Emitting OrganicSemiconductor Device]

The present invention also relates to an organic semiconductor materialfor a non-light-emitting organic semiconductor device containing thecompound of the present invention.

(Non-Light-Emitting Organic Semiconductor Device)

In the present specification, a “non-light-emitting organicsemiconductor device” refers to a device which is not used for thepurpose of emitting light. Particularly, a “non-light-emitting organicsemiconductor device” refers to a device which is not used for thepurpose of emitting visible light. The non-light-emitting organicsemiconductor device preferably uses an electronic element having alayered structure consisting of films. The non-light-emitting organicsemiconductor device includes an organic transistor, an organicphotoelectric conversion element (a solid-state imaging element used fora photosensor, a solar cell used for energy conversion, or the like), agas sensor, an organic rectifying element, an organic inverter, aninformation recording element, and the like. The organic photoelectricconversion element can be used for a photosensor (solid-state imagingelement) and for energy conversion (a solar cell). Among these, anorganic photoelectric conversion element and an organic transistor arepreferable, and an organic transistor is more preferable. That is, theorganic semiconductor material for a non-light-emitting organicsemiconductor device of the present invention is preferably a materialfor an organic transistor as described above.

(Organic Semiconductor Material)

In the present specification, the “organic semiconductor material” is anorganic material showing characteristics of a semiconductor. Just as asemiconductor composed of an inorganic material, the organicsemiconductor is classified into a p-type (hole-transporting) organicsemiconductor material conducting holes as carriers and an n-type(electron-transporting) organic semiconductor material conductingelectrons as carriers.

The compound of the present invention may be used as any of the p-typeorganic semiconductor material and the n-type organic semiconductormaterial, but is preferably used as the p-type. The ease with which thecarriers flow in the organic semiconductor is represented by a carriermobility μ. The higher the carrier mobility μ, the better. The carriermobility μ is preferably equal to or greater than 1×10⁻² cm²/Vs, morepreferably equal to or greater than 1×10⁻¹ cm²/Vs, particularlypreferably equal to or greater than 3×10⁻¹ cm²/Vs, more particularlypreferably equal to or greater than 5×10⁻¹ cm²/Vs, and even moreparticularly preferably equal to or greater than 1 cm²/Vs. The carriermobility μ can be determined by the characteristics of the preparedfield effect transistor (FET) element or by a time-of-flight (TOF)measurement method.

[Organic Semiconductor Film for Non-Light-Emitting Organic SemiconductorDevice]

A first aspect of the organic semiconductor film for anon-light-emitting organic semiconductor device of the present inventionpreferably contains a compound represented by the following Formula (2)and a polymer binder.

In Formula (2), R¹¹ and R¹² each independently represent a hydrogenatom, an alkyl group, an alkenyl group, an alkynyl group, or an alkoxygroup and may have a substituent, and an aromatic portion in Formula (2)may be substituted with a halogen atom.

A second aspect of the organic semiconductor film for anon-light-emitting organic semiconductor device of the present inventioncontains the compound of the present invention.

The organic semiconductor film for a non-light-emitting organicsemiconductor device of the present invention is preferably manufacturedby the method for manufacturing an organic semiconductor film of thepresent invention.

(Material)

The present invention also relates to the first aspect of the organicsemiconductor film for a non-light-emitting organic semiconductor devicecontaining a compound represented by Formula (2), which will bedescribed later, and a polymer binder.

The present invention also relates to the second aspect of the organicsemiconductor film for a non-light-emitting organic semiconductor devicecontaining the compound of the present invention.

As the second embodiment of the organic semiconductor film for anon-light-emitting organic semiconductor device of the presentinvention, an aspect containing the compound of the present inventionbut does not contain a polymer binder.

Furthermore, the second aspect of the organic semiconductor film for anon-light-emitting organic semiconductor device of the present inventionmay contain the compound of the present invention and a polymer binder.

Examples of the polymer binder include an insulating polymer such aspolystyrene, polycarbonate, polyarylate, polyester, polyamide,polyimide, polyurethane, polysiloxane, polysulfone, polymethylmethacrylate, polymethyl acrylate, cellulose, polyethylene, orpolypropylene, a copolymer of these, rubber or a thermoplastic elastomersuch as ethylene-propylene rubber, acrylonitrile-butadiene rubber,hydrogenated nitrile rubber, fluoro-rubber, a perfluoro elastomer, atetrafluoroethylene-propylene copolymer, an ethylene-propylene-dienecopolymer, styrene-butadiene rubber, polychloroprene, polyneoprene,butyl rubber, a methyl/phenyl silicone resin, amethyl/phenylvinyl/silicone resin, a methyl/vinyl/silicone resin, afluorosilicone resin, acryl rubber, ethylene acryl rubber,chlorosulfonated polyethylene, chloropolyethylene, an epichlorohydrincopolymer, a polyisoprene-natural rubber copolymer, polyisoprene rubber,a styrene-isoprene block copolymer, a polyester-urethane copolymer, apolyether-urethane copolymer, a polyether ester thermoplastic elastomer,and polybutadiene rubber, a photoconductive polymer such aspolyvinylcarbazole or polysilane, a conductive polymer such aspolythiophene, polypyrrole, polyaniline, or poly p-phenylenevinylene,and a semiconductor polymer described in, for example, Chemistry ofMaterials, 2014, 26, 647.

One kind of polymer binder may be used singly, or plural kinds thereofmay be used in combination.

The organic semiconductor material may be uniformly mixed with thepolymer binder. Alternatively, the organic semiconductor material andthe polymer binder may be totally or partially in a phase separationstate. From the viewpoint of the charge mobility, a structure, in whichthe organic semiconductor and the binder are in a phase separation statealong the film thickness direction in the film, is the most preferablebecause then the binder does not hinder the organic semiconductor frommoving a charge.

Considering the mechanical strength of the film, a polymer binder havinga high glass transition temperature is preferable. However, for thepurpose of imparting flexibility to the film, a polymer binder having alow glass transition temperature is preferable. Considering the chargemobility, a polymer binder having a structure not containing a polargroup and a conductive polymer are preferable.

The amount of the polymer binder used is not particularly limited.However, in the organic semiconductor film for a non-light-emittingorganic semiconductor device of the present invention, the amount of thepolymer binder used is preferably within a range of 0% to 95% by mass,more preferably within a range of 10% to 90% by mass, even morepreferably within a range of 20% to 80% by mass, and particularlypreferably within a range of 30% to 70% by mass.

In the present invention, because the compound of the present inventionor the compound represented by Formula (2) has the aforementionedstructure, an organic film having excellent film quality can beobtained. Specifically, the compound of the present invention or thecompound represented by Formula (2) has excellent crystallinity, asufficient film thickness can be obtained, and the obtained organicsemiconductor film for a non-light-emitting organic semiconductor deviceof the present invention has excellent quality.

In a case where the organic semiconductor film for a non-light-emittingorganic semiconductor device of the present invention is manufactured bythe method for manufacturing an organic semiconductor film of thepresent invention, the organic semiconductor film becomes an organicfilm having excellent film quality.

EXAMPLES

Hereinafter, the characteristics of the present invention will be morespecifically explained by describing examples and comparative examples.The materials, the amount thereof used, the proportion thereof, thecontent of treatment, the treatment procedure, and the like described inthe following examples can be appropriately modified within a range thatdoes not depart from the gist of the present invention. Accordingly, thescope of the present invention is not limited to the following specificexamples.

Example 1

Compounds described in Table 1 or 2 were synthesized.

<Synthesis Method>

A compound 1 having the following structure that was used in the organictransistor of the present invention was synthesized according to thefollowing synthesis method.

(Synthesis of Intermediate 1)

23.1 ml of tetrahydrofuran was added to 3.93 ml of tetramethylpiperidine(TMP), followed by stirring at −78° C., and 13.8 ml of n-butyllithium(1.6 M hexane solution) was added thereto. Then, the mixture was heatedto 0° C. and stirred for 1 hour, thereby preparing a lithium reagent.

100 ml of tetrahydrofuran was added to 2.969 g (10 mmol) ofthieno[3,2-f:4,5-f′]bis[1]benzothiophene as a known material synthesizedaccording to the synthesis method described in J. Org. Chem. 2005, 70,4502, followed by stirring at −78° C., and the aforementioned lithiumreagent was added dropwise thereto at −78° C. by using a cannula. After2 hours, the reaction solution was cooled to −98° C., and a solutionobtained by dissolving 9.76 g (30 mmol) of dibromodichloroethane in 30ml of tetrahydrofuran was added dropwise thereto by using a cannula.Then, the reaction solution was slowly heated to room temperature from−98° C. and stirred for 15 hours. After the reaction solution was cooledto 0° C., water was added thereto, and the precipitate was separated byfiltration. The solid separated by filtration was recrystallized from1,1,2,2-tetrachloroethane, thereby obtaining 3.95 g (8.70 mmol) of atarget compound (intermediate 1) in the form of solid with light orangecolor. The obtained compound was identified by Nuclear MagneticResonance (¹H-NMR).

¹H-NMR

(tetrachloroethane-d₂, 400 MHz) δ: 7.46 (2H, s), 8.12 (2H, s), 8.45 (2H,s)

(Synthesis of Compound 1)

4.8 ml (4.80 mmol) of decyl magnesium bromide (1.0 mol/L diethylethersolution) was added to the intermediate 1 and cooled to 0° C. At thispoint in time, 4.8 ml (4.80 mmol) of zinc (II) chloride (1.0 mol/Ltetrahydrofuran solution) was added dropwise thereto, thereby preparingan organic zinc reagent. The organic zinc reagent was added to a systemto which 545 mg (1.20 mmol) of the intermediate 1, 49 mg (0.06 mmol) of[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II), and 12 mlof toluene were added, followed by stirring for 20 minutes at roomtemperature. Then, the reaction solution was heated to 70° C. andstirred for 15 hours. After the reaction ended, the reaction solutionwas cooled to room temperature, 50 ml of methanol was added thereto, andthe precipitated solid was separated by filtration. The solid wasdissolved in heated O-dichlorobenzene, passed through celite and silicagel in the heated state, and eluted using O-dichlorobenzene. Thesolution was concentrated using an evaporator and then recrystallizedfrom heated O-dichlorobenzene, thereby obtaining 440 mg (0.763 mmol) ofa target compound 1 in the form of white solid.

The structure of the compound 1 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(tetrachloroethane-d₂, 400 MHz) δ: 0.82 (6H, t, J=7.2 Hz), 1.21-1.37(28H, m), 1.71 (4H, quin, J=7.4 Hz), 2.88 (4H, t, J=7.6 Hz), 7.09 (2H,s), 8.11 (2H, s), 8.39 (2H, s)

Synthesis of Compound 4 (Synthesis Method and NMR)

A compound 4 was synthesized in the same manner as used for synthesizingthe compound 1, except that decyl magnesium bromide (1.0 M diethylethersolution) was changed to butyl magnesium chloride (1.0 M tetrahydrofuransolution).

The structure of the compound 4 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.98 (6H, t, 7.2 Hz), 1.41-1.50 (4H, m), 1.72-1.81(4H, m), 2.94 (4H, t, 7.0 Hz), 7.13 (2H, s), 8.15 (2H, s), 8.44 (2H, s)ppm.

Synthesis of Compound 5

A compound 5 was synthesized in the same manner as used for synthesizingthe compound 1, except that decyl magnesium bromide (1.0 M diethylethersolution) was changed to pentyl magnesium bromide (1.0 M tetrahydrofuransolution).

The structure of the compound 5 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.93 (6H, t, 7.3 Hz), 1.37-1.55 (8H, m), 1.75-1.83(4H, m), 2.94 (t, 7.0 Hz), 7.13 (2H, s), 8.15 (2H, s), 8.44 (2H, s) ppm.

A compound 6 was synthesized according to Tetrahedron 66 (2010)8778-8784.

Synthesis of Compound 11

A compound 11 was synthesized in the same manner as used forsynthesizing the compound 1, except that decyl magnesium bromide (1.0 Mdiethylether solution) was changed to 6-methyloctyl bromide (1.0 Mtetrahydrofuran solution).

The structure of the compound 11 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.84-0.88 (12H, m), 1.08-1.17 (4H, m), 1.30-1.44(14H, m), 1.75-1.83 (4H, m), 2.94 (4H, t, 7.1 Hz), 7.13 (2H, s), 8.15(2H, s), 8.44 (2H, s) ppm.

Synthesis of Compound 18 (Synthesis Method and NMR)

The intermediate 1 (300 mg, 0.66 mmol),2-(2-butoxyethyl)-4,4,5,5-tetramethyl-1,3,2-dioxabolane (452 mg, 1.98mmol), tris(dibenzylideneacetone)dipalladium (0) (Pd₂(dba)₃) (30 mg,0.033 mmol), 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl (RuPhos)(61 mg, 0.132 mmol), t-butoxysodium (381 mg, 4.00 mmol), 7 mL oftoluene, and 7 mL of pure water were mixed together, followed bystirring for 2.5 hours at 80° C. The reaction solution was cooled toroom temperature and subjected to liquid separation by using chloroformand pure water. An organic layer was concentrated through distillationunder reduced pressure and then purified by column chromatography(sequential development using silica gel, hexane:ethyl acetate=3:1,hexane:ethyl acetate=2:1, and hexane:ethyl acetate=1:1), therebyobtaining 140 mg (0.282 mmol) of a compound 18 as a white solid.

The obtained compound was identified by ¹H-NMR.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.94 (6H, t, 7.3 Hz), 1.36-1.46 (4H, m), 1.58-1.65(4H, m), 3.20 (4H, t, 7.1 Hz), 3.51 (4H, t, 7.0 Hz), 3.51 (4H, t, 7.0Hz), 3.77 (4H, t, 7.2 Hz), 7.20 (2H, s), 8.15 (2H, s), 8.46 (2H, s) ppm.

Synthesis of Compound 20

A compound 20 was synthesized in the same manner as used forsynthesizing the compound 1, except that decyl magnesium bromide (1.0 Mdiethylether solution) was changed to 4-butoxybutyl magnesium bromide(1.0 M THF solution).

The structure of the compound 20 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.93 (6H, t, 7.4 Hz), 1.34-1.43 (4H, m), 1.53-1.60(4H, m), 1.68-1.75 (4H, m), 1.83-1.91 (4H, m), 2.97 (4H, t, 7.3 Hz),3.42 (4H, t, 7.0 Hz), 3.47 (4H, t, 7.0 Hz) ppm.

Synthesis of Compound 29

(Synthesis of Intermediate 2)

An intermediate 2 was synthesized in the same manner as used forsynthesizing the intermediate 1, except that the amounts of all of thetetramethylpiperidine (TMP), n-butyllithium, and dibromodichloroethanewere halved.

(Synthesis of Intermediate 3)

An intermediate 3 was synthesized in the same manner as used forsynthesizing the compound 4, except that the intermediate 1 was changedto the intermediate 2, and the equivalents of organic zinc reagent and[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II) werehalved.

(Synthesis of Intermediate 4)

An intermediate 4 was synthesized in the same manner as used forsynthesizing the intermediate 2, except that the intermediate 3 was usedinstead of thieno[3,2-f:4,5-f′]bis[1]benzothiophene.

A compound 29 was synthesized in the same manner as used forsynthesizing the compound 5, except that the intermediate 1 was changedto the intermediate 4, and the equivalents of organic zinc reagent and[1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium (II) werehalved.

The structure of the compound 29 was identified by ¹H-NMR. The resultsare shown below.

¹H-NMR

(CDCl₃, 400 MHz) δ: 0.92 (3H, t, 7.2 Hz), 0.98 (3H, t, 7.2 Hz),1.38-1.52 (6H, m), 1.73-1.82 (4H, m), 2.92-2.97 (4H, m), 7.13 (2H, s),8.15 (2H, s), 8.44 (2H, s) ppm.

[Synthesis of Comparative Compound]

A comparative compound 1 having the following structure was synthesizedaccording to the synthesis method described in J. Org. Chem. 2005, 70,4502.

The following comparative compounds 2 to 6 were synthesized withreference to JP2013-235903A, CN102206225A, and WO2011/126225A,JP2009-302463A, and JP2010-177642A respectively. The comparativecompounds 2 and 3 were measured by gel permeation chromatography (GPC),and as a result, it was confirmed that they have a weight-averagemolecular weight (Mw) of 40,000.

Examples 1-1 to 1-8 and Comparative Elements 1-1 to 1-4

<Preparation/Evaluation of Element>

Through high-performance liquid chromatography, it was confirmed thatthe materials used for preparing elements had purity (area ratio forabsorption intensity at 254 nm) of equal to or higher than 99.0%.

A semiconductor active layer (organic semiconductor film) was formedusing a compound alone.

Any one of compounds or comparative compounds 1 to 4 described in thefollowing table was prepared into a 0.1% by mass solution by beingdissolved in anisole as a solvent and then heated to 50° C. The solutionwas used as a coating solution for an organic semiconductor device(referred to as a coating solution as well).

In the elements 1-1 to 1-8 and the comparative elements 1-1 to 1-4, anorganic semiconductor film was formed by the method shown in FIGS. 4A to4C. Herein, “1-1 to 1-8” means 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, 1-7, and1-8. The same will be also applied in a case where branch numbers aredescribed using “to”. Specifically, the organic semiconductor film wasformed as below.

A 25 mm×25 mm substrate prepared by forming a thermally oxidized SiO₂film having a thickness of 200 nm on the surface of an n-type siliconsubstrate (thickness: 0.4 mm) was used as a substrate A. The surface ofthe thermally oxidized film of the substrate A was cleaned withultraviolet (UV)-ozone and then treated withβ-phenethyltrimethoxysilane.

On the surface of the substrate A treated withβ-phenethyltrimethoxysilane, a member B was placed on the centralportion of the substrate A as shown in FIG. 4A such that the substrate Aand the member B contacted each other. As the member B, a substance madeof glass and having a size of 10 mm (length)×2 mm (width)×5 mm (height)was used. The transverse direction (X-axis direction) in FIG. 4A is thewidth direction of the member B; the vertical direction (Z-axisdirection) in FIG. 4A is the height direction of the member B; and thevertical direction (Y-axis direction) in FIG. 4B2 is the longitudinaldirection of the member B.

The substrate was heated to 50° C., and one drop (about 0.05 ml) of thecoating solution prepared by the method described above was placed ontothe substrate by using a pipette from the lateral side of the member Bsuch that the drop contacted both of the substrate A and the member B asshown in FIG. 4A. As a result, as shown in FIGS. 4B1 and 4B2, thecoating solution was dropped onto a portion within the surface of thesubstrate A. In the interface between the coating solution and thesubstrate B, a concave meniscus was formed.

As shown in FIG. 4C, in a state where the substrate A and the member Bwere caused to remain in contact with each other, and the positionalrelationship between the substrate A and the member B were maintained,the coating solution was air-dried. Then, the coating solution was driedunder reduced pressure for 8 hours at 60° C. at a pressure of 10⁻³ MPasuch that crystals of any one of the compounds or comparative compounds1 to 4 described in the following table were precipitated, therebyforming an organic semiconductor film. Whether or not crystals wereprecipitated was checked by observation using a polarizing microscope.

The obtained organic semiconductor film was used as a semiconductoractive layer and covered with a mask. Then, F4-TCNQ with a thickness of1 nm as a charge injection acceptor and a gold electrode with athickness of 40 nm were vapor-deposited thereon, thereby obtaining abottom gate/top contact-type organic transistor element for measuringFET characteristics. The obtained organic transistor element was takenas the elements 1-1 to 1-8 and the comparative elements 1-1 to 1-4. Theelements 1-1 to 1-8 and the comparative elements 1-1 to 1-4 were takenas organic transistor elements of Examples 1-1 to 1-8 and Comparativeexamples 1 to 4.

<Evaluation>

By using a semiconductor parameter analyzer (4156C manufactured byAgilent Technologies) connected to a semi-automatic prober (AX-2000manufactured by Vector Semiconductor Co., Ltd.), the FET characteristicsof the organic transistor elements as the elements 1-1 to 1-8 and thecomparative elements 1-1 to 1-4 were evaluated under a normalpressure/atmosphere.

The obtained results are shown in the following Table 3.

(a) Carrier Mobility

Between the source electrode and the drain electrode of each organicfilm transistor element (FET element), a voltage of −80 V was applied,and the gate voltage was varied within a range of 20 V to −100 V. Inthis way, a carrier mobility μ was calculated using the followingequation showing a drain current I_(d).I _(d)=(w/2L)μC _(i)(V _(g) −V _(th))²

(In the equation, L represents a gate length, W represents a gate width,C_(i) represents a capacity of the insulating layer per unit area, V_(g)represents a gate voltage, and V_(th) represents a threshold voltage.)

TABLE 3 Organic Carrier Element semiconductor mobility No. material(cm²/Vs) Note Element 1-1 Compound 1 6.0 Present invention Element 1-2Compound 4 2.9 Present invention Element 1-3 Compound 6 1.0 Presentinvention Element 1-4 Compound 21 1.5 Present invention Element 1-5Compound 24 2.1 Present invention Element 1-6 Compound 33 1.3 Presentinvention Element 1-7 Compound 37 1.8 Present invention Element 1-8Compound 40 1.6 Present invention Comparative Comparative 0.1Comparative element 1-1 compound 1 Example Comparative Comparative 0.01Comparative element 1-2 compound 2 Example Comparative Comparative 0.02Comparative element 1-3 compound 3 Example Comparative Comparative 0.006Comparative element 1-4 compound 4 Example

From the above Table 3, it was understood that the organic transistorelements as the elements 1-1 to 1-8 of the present invention have highcarrier mobility and can be preferably used as organic semiconductormaterials.

In contrast, it was understood that the organic transistor elements asthe comparative elements 1-1 to 1-4 in which the comparative compounds 1to 4 were used as organic semiconductor materials in the semiconductoractive layer have low carrier mobility.

Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-3

In Examples 2-1 to 2-14 and Comparative Examples 2-1 to 2-3, a bottomgate/bottom contact-type organic transistor element was prepared. Thedetails are described below.

An anisol solution containing 0.1% by mass of the compound 1 was heatedto 100° C. and used as a coating solution for an organic semiconductordevice. In a nitrogen atmosphere, the solution was cast onto a substratefor measuring FET characteristics heated to 90° C., thereby obtaining anon-light-emitting organic transistor element 2-1. As the substrate formeasuring FET characteristics, a silicon substrate having a bottomgate/bottom contact structure was used which included chromium/gold(gate width W=100 mm, gate length L=100 μm) arranged to form a combpattern as source and drain electrodes and included SiO₂ (filmthickness: 200 nm) as an insulating layer. The obtained organictransistor element was taken as an element 2-1. The element 2-1 wastaken as an organic transistor element of Example 2-1.

Elements 2-2 to 2-14 and comparative elements 2-1 to 2-3 were preparedin the same manner as used for preparing the element 2-1, except that,in preparing the organic transistor element as the element 2-1, any oneof the compounds or comparative compounds described in Table 2 was usedinstead of the compound 1. The element 2-6 was obtained by mixing thecompound 4 and the compound 5 together such that the concentration ofeach of the compounds became 0.05% by mass.

<Evaluation>

For the elements 2-2 to 2-14 and the comparative elements 2-1 to 2-3,FET characteristics of an organic transistor element were evaluated inthe same manner as in Example 1-1. The results are shown in thefollowing Table 4.

TABLE 4 Organic Carrier semiconductor mobility Element No. material(cm²/Vs) Note Element 2-1 Compound 1 0.50 Present invention Element 2-2Compound 2 0.77 Present invention Element 2-3 Compound 3 0.52 Presentinvention Element 2-4 Compound 4 0.95 Present invention Element 2-5Compound 5 0.52 Present invention Element 2-6 Compound 4/ 0.71 Presentinvention compound 5 Element 2-7 Compound 6 0.30 Present inventionElement 2-8 Compound 10 0.14 Present invention Element 2-9 Compound 260.31 Present invention Element 2-10 Compound 28 0.64 Present inventionElement 2-11 Compound 29 0.33 Present invention Element 2-12 Compound 300.45 Present invention Element 2-13 Compound 32 0.42 Present inventionElement 2-14 Compound 40 0.32 Present invention Comparative Comparative0.03 Comparative element 2-1 compound 1 Example Comparative Comparative<0.001 Comparative element 2-2 compound 2 Example ComparativeComparative 0.01 Comparative element 2-3 compound 6 Example

From the above Table 4, it was understood that the organic transistorelements as the elements 2-2 to 2-14 of the present invention have highcarrier mobility and can be preferably used as organic semiconductormaterials.

In contrast, it was understood that the organic transistor elements asthe comparative elements 2-1 to 2-3 in which the comparative compounds1, 2, and 6 were used as organic semiconductor materials in asemiconductor active layer have low carrier mobility.

Examples 3-1 to 3-29 and Comparative Examples 3-1 to 3-5

Al to be a gate electrode was vapor-deposited (thickness: 50 nm) onto aglass substrate (Eagle XG: manufactured by Corning Incorporated). Ontothe Al, a composition for forming a gate insulating film (a propyleneglycol monomethyl ether acetate (PGMEA) solution (concentration of solidcontents: 2% by mass) containing polyvinylphenol/melamine=1 part bymass/1 part by mass) was applied by spin coating, followed by baking for60 minutes at 150° C., thereby forming a gate insulating film having afilm thickness of 400 nm. On the gate insulating film, by using a silverink (H-1, manufactured by Mitsubishi Materials Corporation) and an inkjet device DMP-2831 (manufactured by FUJIFILM Dimatix Inc.), patterns ofa source electrode and a drain electrode (channel length: 40 μm, channelwidth: 200 μm) were drawn. Then, the resultant was sintered by beingbaked for 30 minutes at 180° C. in an oven such that source and drainelectrodes were formed, thereby obtaining an element substrate forevaluating thin film transistor (TFT) characteristics.

Onto the element substrate for evaluating TFT characteristics, each ofthe coating solutions for an organic semiconductor device (an organicsemiconductor material (0.50% by mass), a polymer (0.025% by mass), andtoluene) described in the following Table 5 was applied by drop casting,and then the element substrate was dried for 10 minutes at 100° C. on ahot plate such that an organic semiconductor layer was formed, therebyobtaining a bottom gate/bottom contact-type organic transistor element.The obtained organic transistor element was taken as elements 3-1 to3-29 and comparative elements 3-1 to 3-5. The elements 3-1 to 3-29 andthe comparative elements 3-1 to 3-5 were taken as organic transistorelements of Examples 3-1 to 3-29 and Comparative elements 3-1 to 3-5. Inthe following table, F8T2 represents[Poly[(9,9-dioctyl-9H-fluorene-2,7-diyl)-alt-2,2′-bithiophene]-5,5′-diyl)]](manufactured by Sigma-Aldrich Co., LLC., Mn>20,000); PMMA representsPolymethyl methacrylate (manufactured by Sigma-Aldrich Co., LLC.,Mw˜15,000); PαMS represents Poly(α-methylstyrene) (manufactured bySigma-Aldrich Co., LLC., Mw=43,700); and PS represents Polystyrene(manufactured by Sigma-Aldrich Co., LLC., Mw=2,000,000).

<Evaluation>

For the elements 3-1 to 3-29 and the comparative elements 3-1 to 3-5,the FET characteristics of an organic transistor element were evaluatedin the same manner as in Example 1. The results are shown in thefollowing Table 5.

TABLE 5 Organic Carrier semiconductor Polymer mobility Element No.material (binder) (cm²/Vs) Note Element 3-1 Compound 4 F8T2 0.35 Presentinvention Element 3-2 Compound 7 — 0.27 Present invention Element 3-3Compound 8 — 0.11 Present invention Element 3-4 Compound 9 — 0.31Present invention Element 3-5 Compound 11 PMMA 0.01 Present inventionElement 3-6 Compound 12 — 0.01 Present invention Element 3-7 Compound 13— 0.02 Present invention Element 3-8 Compound 14 — 0.05 Presentinvention Element 3-9 Compound 15 — 0.01 Present invention Element 3-10Compound 16 — 0.01 Present invention Element 3-11 Compound 17 — 0.01Present invention Element 3-12 Compound 17 PαMS 0.01 Present inventionElement 3-13 Compound 18 — 0.02 Present invention Element 3-14 Compound19 — 0.05 Present invention Element 3-15 Compound 20 — 0.05 Presentinvention Element 3-16 Compound 21 — 0.03 Present invention Element 3-17Compound 22 — 0.01 Present invention Element 3-18 Compound 23 — 0.01Present invention Element 3-19 Compound 24 — 0.01 Present inventionElement 3-20 Compound 25 — 0.31 Present invention Element 3-21 Compound27 — 0.30 Present invention Element 3-22 Compound 31 — 0.20 Presentinvention Element 3-23 Compound 33 — 0.23 Present invention Element 3-24Compound 34 PαMS 0.02 Present invention Element 3-25 Compound 35 — 0.01Present invention Element 3-26 Compound 36 — 0.02 Present inventionElement 3-27 Compound 37 — 0.02 Present invention Element 3-28 Compound38 — 0.04 Present invention Element 3-29 Compound 39 PS 0.01 Presentinvention Comparative Comparative — 0.002 Comparative element 3-1compound 1 Example Comparative Comparative — <0.001 Comparative element3-2 compound 2 Example Comparative Comparative — <0.001 Comparativeelement 3-3 compound 4 Example Comparative Comparative — <0.001Comparative element 3-4 compound 5 Example Comparative Comparative —<0.001 Comparative element 3-5 compound 6 Example

From the above Table 5, it was understood that the organic transistorelements as the elements 3-1 to 3-29 of the present invention have highcarrier mobility and can be preferably used as organic semiconductormaterials.

In contrast, it was understood that the organic transistor elements asthe comparative elements 3-1 to 3-5 in which the comparative compounds1, 2, and 4 to 6 were used as organic semiconductor materials in asemiconductor active layer have low carrier mobility.

Examples 4-2 to 4-4 and 4-6 to 4-8

<Preparation Example of TFT Element by Printing Method>

—Ink Jet Method—

The element substrate for evaluating TFT characteristics manufactured inExample 3-1 was coated with a coating solution for an organicsemiconductor device (the organic semiconductor compound, the polymer(binder), the solvent, and the concentration described in Table 6) by anink jet method, thereby forming an organic semiconductor film andobtaining an organic transistor element. By using DPP 2831 (manufacturedby FUJIFILM Graphic Systems, Inc.) as an ink jet device and a 10 pLhead, a solid film was formed at a jetting frequency of 2 Hz and a dotpitch of 20 μm. The film was then dried for 1 hour at 70° C., therebypreparing an organic semiconductor layer.

—Flexographic Printing Method—

By a flexographic printing method, the element substrate for evaluatingTFT characteristics manufactured in Example 3-1 was coated with acoating solution for an organic semiconductor device (the organicsemiconductor compound, the polymer (binder), the solvent, and theconcentration described in Table 6 and 0.05% by mass of BYK-323(manufactured by BYK Additives & Instruments) as a surfactant), therebyforming an organic semiconductor film and obtaining an organictransistor element. As a printing device, a flexographic printingsuitability tester F1 (manufactured by IGT Testing Systems) was used,and as a resin plate for flexographic printing, AFP DSH 1.70%(manufactured by Asahi Kasei Corporation.)/solid image was used. Under apressure of 60 N applied between the resin plate for flexographicprinting and the element substrate for evaluating TFT characteristics,printing was performed at a transport rate of 0.4 m/sec, and then thesubstrate was dried as it is for 2 hours at room temperature lower than40° C., thereby preparing an organic semiconductor layer and obtaining abottom gate/bottom contact-type organic transistor element. The obtainedorganic transistor element was taken as elements 4-2 to 4-4 and 4-6 to4-8. The elements 4-2 to 4-4 and 4-6 to 4-8 were taken as organictransistor elements of Examples 4-2 to 4-4 and 4-6 to 4-8. Herein, allof those used as an ink in the elements 4-6 to 4-8 had a viscosity ofequal to or greater than 10 mPa·s.

TABLE 6 Concentration Organic semiconductor/ Carrier Element OrganicPolymer polymer Printing mobility No. semiconductor (binder) Solvent (wt%) method (cm²/Vs) Note Element Compound 5  — Tetralin 0.4 Ink jet 0.65Example 4-2 Element Compound 17 — Toluene 0.5 Ink jet 0.13 Example 4-3Element Compound 31 PMMA Mesitylene 1.0 Ink jet 0.35 Example 4-4 ElementCompound 4  PαMS Tetralin 0.4/1.0 Flexography 0.20 Example 4-6 ElementCompound 29 PS Tetralin 0.5/1.0 Flexography 0.25 Example 4-7 ElementCompound 38 PαMS Tetralin 1.5/1.0 Flexography 0.12 Example 4-8

As shown in Table 6, even in a case where a film was formed by an inkjet method or a flexographic printing method, an organic transistorelement having excellent characteristics that has high carrier mobilityand can be preferably used as an organic semiconductor material wasobtained.

EXPLANATION OF REFERENCES

-   -   11: substrate    -   12: electrode    -   13: insulator layer    -   14: semiconductor active layer (organic substance layer, organic        semiconductor layer)    -   15 a, 15 b: electrode    -   31: substrate    -   32: electrode    -   33: insulator layer    -   34 a, 34 b: electrode    -   35: semiconductor active layer (organic substance layer, organic        semiconductor layer)    -   41: coating solution    -   42: substrate A    -   43: member B

What is claimed is:
 1. A compound which is represented by the followingFormula (2A);

in Formula (2A), R¹¹ and R¹² each independently represent a halogenatom, and an aromatic portion in Formula (2A) may be substituted with ahalogen atom.
 2. The compound according to claim 1, wherein the compoundrepresented by Formula (2A) is an intermediate of a compound which isrepresented by the following Formula (2), wherein in Formula (2), R¹¹and R¹² each independently have 3 to 30 carbon atoms in total andrepresent an alkenyl group, an alkynyl group or an alkoxy group and mayhave a substituent, or the compound represented by Formula (2) satisfiesthe following condition A, B, C, or D;

in Formula (2), an aromatic portion in Formula (2) may be substitutedwith a halogen atom; condition A: in Formula (2), R¹¹ and R¹² eachindependently have 3 to 30 carbon atoms in total and represent anunsubstituted linear alkyl group having an even number of carbon atomswithin a range of 8 to 10 carbon atoms, an unsubstituted linear alkylgroup having an odd number of carbon atoms within a range of 3 to 15carbon atoms, a substituted linear alkyl group having 3 to 15 carbonatoms, or a substituted or unsubstituted branched alkyl group having 3to 18 carbon atoms; condition B: in Formula (2), R¹¹ and R¹² eachindependently have 3 to 30 carbon atoms in total and represent anunsubstituted linear alkyl group having an even number of carbon atomswithin a range of 2 to 4 carbon atoms; condition C: in Formula (2), R¹¹and R¹² each independently have 3 to 30 carbon atoms in total andrepresent a substituted alkyl group having 1 or 2 carbon atoms;condition D: in Formula (2), R¹¹ and R¹² each independently have 3 to 30carbon atoms in total, and R¹¹ and R¹² have different structures.